Network node and method therein in a radio communications network

ABSTRACT

A method performed by a network node to change a transport path for a user plane session in a radio communications network. The path prolongs along a first part between an antenna endpoint of a network node and a Packet Processing Function (PPF) instance serving the network node and a second part between the PPF instance and a Core Network (CN) endpoint. The network node identifies available CN endpoints in a CN, available PPF instances in a Radio Access Network (RAN) and of available antenna endpoints in the RAN that are available for the user plane session and comprises a number of possible transport paths for the user plane session. When detecting a change event related to the user plane session, the network node controls whether or not to change the transport path to any of the a number of possible transport paths for the user plane session.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National stage of International Application No.PCT/SE2017/050864, filed Aug. 29, 2017, which claims priority toInternational Application No. PCT/SE2017/050544, filed May 23, 2017,which are all hereby incorporated by reference.

TECHNICAL FIELD

Embodiments herein relate to a network node and methods therein. Inparticular, they relate to controlling whether or not to change atransport path for a user plane session in a radio communicationsnetwork (100).

BACKGROUND

In a typical wireless communication network, wireless devices, alsoknown as wireless communication devices, mobile stations, stations (STA)and/or user equipments (UE), communicate via a Radio Access Network(RAN) to one or more core networks (CN). The RAN covers a geographicalarea which is divided into service areas or cell areas, which may alsobe referred to as a beam or a beam group, with each service area or cellarea being served by a network node such as a radio access node e.g., aWi-Fi access point or a radio base station (RBS), which in some networksmay also be denoted, for example, a “NodeB” or “eNodeB”. A service areaor cell area is a geographical area where radio coverage is provided bythe network node. The radio network node communicates over an airinterface operating on radio frequencies with the wireless device withinrange of the radio network node.

A Universal Mobile Telecommunications System (UMTS) is a thirdgeneration (3G) telecommunication network, which evolved from the secondgeneration (2G) Global System for Mobile Communications (GSM). The UMTSterrestrial radio access network (UTRAN) is essentially a RAN usingwideband code division multiple access (WCDMA) and/or High Speed PacketAccess (HSPA) for user equipments. In a forum known as the ThirdGeneration Partnership Project (3GPP), telecommunications supplierspropose and agree upon standards for third generation networks, andinvestigate enhanced data rate and radio capacity. In some RANs, e.g. asin UMTS, several radio network nodes may be connected, e.g., bylandlines or microwave, to a controller node, such as a radio networkcontroller (RNC) or a base station controller (BSC), which supervisesand coordinates various activities of the plural radio network nodesconnected thereto. This type of connection is sometimes referred to as abackhaul connection. The RNCs and BSCs are typically connected to one ormore core networks.

Specifications for the Evolved Packet System (EPS), also called a FourthGeneration (4G) network, have been completed within the 3rd GenerationPartnership Project (3GPP) and this work continues in the coming 3GPPreleases, for example to specify a Fifth Generation (5G) network. TheEPS comprises the Evolved Universal Terrestrial Radio Access Network(E-UTRAN), also known as the Long Term Evolution (LTE) radio accessnetwork, and the Evolved Packet Core (EPC), also known as SystemArchitecture Evolution (SAE) core network. E-UTRAN/LTE is a variant of a3GPP radio access network wherein the radio network nodes are directlyconnected to the EPC core network rather than to RNCs. In general, inE-UTRAN/LTE the functions of an RNC are distributed between the radionetwork nodes, e.g. eNodeBs in LTE, and the core network. As such, theRAN of an EPS has an essentially “flat” architecture comprising radionetwork nodes connected directly to one or more core networks, i.e. theyare not connected to RNCs. To compensate for that, the E-UTRANspecification defines a direct interface between the radio networknodes, this interface being denoted the X2 interface.

Multi-antenna techniques can significantly increase the data rates andreliability of a wireless communication system. The performance is inparticular improved if both the transmitter and the receiver areequipped with multiple antennas, which results in a Multiple-InputMultiple-Output (MIMO) communication channel. Such systems and/orrelated techniques are commonly referred to as MIMO.

As mentioned above, the 3GPP is currently working on standardization ofthe 5th generation of radio access system, which also is referred to asNew Radio (NR). A Radio Control Function (RCF) is in this exampleincluded in a Radio Control Node (RCN). An evolved architecture for theRAN is foreseen, both for LTE Evolution and New Radio tracks of 5G. Thisincludes a solution where radio base stations may be split into partsfor radio control, packet processing, and Radio Nodes (RNs) withbase-band processing and radio units.

3GPP is currently working on standardization of Release 14 of the LTEconcept. In FIG. 1, the LTE architecture including RAN nodes such aseNBs, Home eNBs (HeNBs), HeNB GateWay (GW) and evolved packet core nodessuch as Mobility Management Entity (MME)/Serving Gateway (S-GW). FIG. 1depicts logical interfaces such as an S1 interface connecting HeNBs/eNBsto the MME/S-GW and HeNBs to the HeNB GW, while an X2 interface isconnecting peer eNBs/HeNBs, optionally via an X2 GW.

Network Slicing

Network slicing is about creating logically separated partitions of thenetwork, addressing different business purposes. These network slicesare logically separated to a degree that they can be regarded andmanaged as networks of their own.

This is a new concept that applies to both LTE Evolution and new 5G RATalso referred to as NextGen NR System. The key driver for introducingnetwork slicing is business expansion, i.e. improving the cellularoperator's ability to serve other industries, e.g., by offeringconnectivity services with different network characteristics such ase.g. performance, security, and robustness.

The current working assumption is that there will be one RANinfrastructure that will connect to several Evolved Packet Core (EPC)instances, one EPC instance per network slice. As the EPC functions arebeing virtualized, it is assumed that the operator shall instantiate anew Core Network (CN) when a new slice should be supported. Thisarchitecture is shown in FIG. 2. Slice 0 may for example be a MobileBroadband slice and Slice 1 may for example be a Machine TypeCommunication network slice.

LTE Architecture Evolution

It is not yet specified by 3GPP how the LTE architecture should evolveto meet the challenges of 5G. However, in 3GPP TR 23.799, an outline ofan initial high level architecture view for 5G (NextGen) system which isshown in FIG. 3 wherein

NG2 is a reference point for the control plane between NextGen (R)AN andNextGen Core.

NG3 is a reference point for the user plane between NextGen (R)AN andNextGen Core.

NG1 is a reference point for the control plane between NextGen UE andNextGen Core.

NG6 is a reference point between the NextGen Core and the data network.Data network may be an operator external public or private data networkor an intra-operator data network, e.g. for provision of IMS services.This reference point corresponds to SGi, which is the reference pointbetween the Packet Data Network Gateway (PDN GW) and the packet datanetwork, for 3GPP accesses.

It is assumed that the above NextGen reference points will be theevolved counterparts of the LTE interfaces and that any new RAT would beintegrated with the LTE radio interface at RAN level in a similarfashion as the way LTE Dual Connectivity is defined.

S1 Control Plane/NG2

S1 Control Plane interface is defined between MME and eNB, and isdescribed in 3GPP specs TS 36.300, TS 36.410, TS 36.411, TS 36.412 andTS 36.413. The control plane stack is shown in FIG. 4. In the bottom ofthe control plane stack lays a Physical Layer and above a data linklayer. Above the data link layer is the transport network layer which isbased on Internet Protocol (IP) transport, and on top of IP, an StreamControl Transmission Protocol (SCTP) layer is added for reliabletransport of signaling messages.

S1 User Plane (S1-U)/NG3

The user plane protocol stack of S1 Interface User Plane for eNB-S-GW isshown in FIG. 5. For 5G, it is assumed that NG2 will have a similarprotocol stack as in S1-AP. S1 The User Plane interface is definedbetween S-GW and eNB, and is described in 3GPP specs TS 36.300, TS36.410, TS 36.411, TS 36.414 and TS 29.281.

In the bottom of the user plane stack lays a Physical Layer and above adata link layer. Above the data link layer is the transport networklayer is based on IP transport, and on top of IP, User Datagram Protocol(UDP) and GPRS Tunneling Protocol User Plane (GTP-U) is added fortunneling of UE eRAB individual user data. RAB stands for Radio AccessBearer while eRAN (E-RAB) stands for e-UTRAN Radio Access Bearer. GPRSmeans General Packet Radio Service. The GTP-U Destination Port numbervalue for the S1-U connection is 2152. For 5G, it is assumed that forNG3 interface will have a similar protocol stack as in S1-U.

S1 User Plane/NG3 Connection Setup

For LTE, the EPS bearer service architecture from 3GPP TS 36.300 isshown in FIG. 6 between a UE and eNB in E-UTRAN, via S-GW and PacketData Network (PDN) Gateway (P-GW) in EPC, and a Peer entity at theInternet. An EPS bearer which may comprise an E-RAB, is the level ofgranularity for bearer level Quality of server (QoS) control in theEPC/E-UTRAN. That is, Service Data Flows mapped to the same EPS bearerreceive the same bearer level packet forwarding treatment, e.g.scheduling policy, queue management policy, rate shaping policy, RLCconfiguration, etc.

An E-RAB transports the packets of an EPS bearer between the UE and theEPC. When an E-RAB exists, there is a one-to-one mapping between thisE-RAB and an EPS bearer. An S1 bearer transports the packets of an E-RABbetween an eNodeB and a Serving GW, where a S1 bearer corresponds to aGTP-U tunnel.

For 5G, currently the following agreement has been settled according to3GPP TR 23.799 V1.2.0.

A PDU Session is an association between the UE and a data network thatprovides a PDU connectivity service. The type of the associationincludes IP type, Ethernet type and non-IP type.

The User Plane format in NextGen on NG3 and between UP functions shallsupport per PDU Session tunneling, i.e. there is one tunnel per PDUSession between a pair of Network Functions (NFs) e.g. between a RANnode and a UP function in the CN and between two UP functions in the CN.All QoS classes of a session share the same outer IP header, but theencapsulation header may carry QoS markings.

The transport protocol for 5G in NG3 is not yet decided, but it can beassumed that this protocol should have similar characteristics as GTP-U.

Figure below shows the architecture difference between S1-U in LTE andNG3 in 5G.

FIG. 7 shows architectural differences between S1-U in LTE and NG3 in5G. According to current standard and agreement within 3GPP, the sourceand destination transport (IP) addresses of the GTP-U tunnel will bedecided first:

-   -   During setup of E-RAB in LTE    -   During setup of PDN session in 5G.

The difference as shown in FIG. 7 is that in LTE, within the PDNsession, an S1 bearer will be established for each service data flowbetween RAN and CN, while in 5G, a single PDN bearer will be establishedfor PDN session, and each service data flow will be transmitted as a QoSflow within the PDN bearer.

Currently, reconfiguration of S1-U is possible but it can only beinitiated by MME used for load balancing of S-GW pool. An S-GW pool is anumber of S-GW within the same CN for load sharing of S1-U connectionstowards RAN.

Setup and Configuration Updates/Transfer Using S1AP/S10

S1 Setup Procedure

The S1 Setup procedure, described in 3GPP 36.300, is used to exchangeconfigured data which is required in the MME and in the eNB respectivelyto ensure a proper interoperation. The S1 Setup procedure is triggeredby the eNB. The S1 Setup procedure is the first S1Application Protocol(AP) procedure which will be executed.

The eNB initiates the S1 Setup procedure by sending the S1 SETUP REQUESTmessage including supported TAs and broadcasted PLMNs to the MME.

In the successful case the MME responds with the S1 SETUP RESPONSEmessage which includes served PLMNs as well as a relative MME capacityindicator to achieve load balanced MMEs in the pool area.

eNB Configuration Update Procedure

The eNB Configuration Update procedure, described in 3GPP 36.300, isused to provide updated configured data in eNB. The eNB ConfigurationUpdate procedure is triggered by the eNB.

The eNB initiates the eNB Configuration Update procedure by sending theENB CONFIGURATION UPDATE message including updated configured data likesupported TAs and broadcasted PLMNs to the MME. In case one or moresupported TA(s) needs to be updated, the eNB shall provide the wholelist of TA(s), including those which has not been changed, in the ENBCONFIGURATION UPDATE message.

The MME responds with the ENB CONFIGURATION UPDATE ACKNOWLEDGE messageto acknowledge that the provided configuration data are successfullyupdated.

The MME shall overwrite and store the received configuration data whichare included in the ENB CONFIGURATION UPDATE message. Configuration datawhich has not been included in the ENB CONFIGURATION UPDATE message areinterpreted by the MME as still valid. For the provided TA(s) the MMEshall overwrite the whole list of supported TA(s).

MME Configuration Update Procedure

The MME Configuration Update procedure, described in 3GPP 36.300, isused to provide updated configured data and changes of the relative MMEcapacity values in the MME. The MME Configuration Update procedure istriggered by the MME.

The MME initiates the MME Configuration Update procedure by sending theMME CONFIGURATION UPDATE message including updated configured data likeserved PLMNs and changes of the relative MME capacity values to the eNB.

The eNB responds with the MME CONFIGURATION UPDATE ACKNOWLEDGE messageto acknowledge that the provided configuration data and the relative MMEcapacity values are successfully updated.

The eNB shall overwrite and store the received configuration data andrelative MME capacity values which are included in the MME CONFIGURATIONUPDATE message. Configuration data which has not been included in theMME CONFIGURATION UPDATE message are interpreted by the eNB as stillvalid.

Configuration Transfer Function

Configuration transfer function, described in 3GPP TS 36.300, is ageneric mechanism that allows the request and transfer of RANconfiguration information (e.g. SON information) between two RAN nodesvia the core network through S1AP.

The eNB Configuration Transfer procedure, is initiated by the eNB torequest and/or transfer RAN configuration information via the corenetwork, by sending the eNB CONFIGURATION TRANSFER message to the MME.The eNB CONFIGURATION TRANSFER message contains RAN configurationinformation (e.g. SON information) and other relevant information suchas the routing address which identifies the final RAN destination node.

The MME Configuration Transfer procedure, is initiated by the MME bysending the MME CONFIGURATION TRANSFER message to the eNB. The MMECONFIGURATION TRANSFER message contains RAN configuration information(e.g. SON information) and other relevant information.

The Configuration Transfer Tunnel message between two MMEs according to3GPP TS 29.274. is used to tunnel eNodeB Configuration Transfer messagesfrom a source MME to a target MME over the S10 interface. The purpose ofthe eNodeB Direct Configuration Transfer is to transfer information froman eNodeB to another eNodeB in unacknowledged mode.

Connected Mode Mobility Functions

Once an UE has been registered to a PLMN and enters RRC/ECM connectedmode, Handover, release with redirection and RRC-connectionre-establishment and other mobility related procedures will occur. Theseprocedures are described in detailed way in 3GPP TS 36.331, 3GPP TS23.401. In connected mode, RAN selects the cell to serve the UE and ismainly based on:

-   -   Radio and load conditions of cells in different frequency layers    -   Optionally, RAN/eNB may consider allowed PLMNs (based on current        registered PLMN and any possible Equivalent PLMNs)        Forbidden/Allowed TA if information is provided when selecting        cell as targets for handover or release with redirection.

UE should also be able to initiate NAS procedure, e.g. Tracking AreaUpdate if necessary also in connected mode.

RAN/eNB receives information from different entities which is useful inconnected mode mobility functions. Examples on how connected modemobility configuration, evaluation and preparation are performed areshown in FIG. 8, FIG. 9 and FIG. 10.

See the following example actions and messages in FIG. 8 showing whatinformation about the neighboring cells has been spread to differententities during X2 setup, X2: Initial Context Setup, RRC:SIB messagesand RRC measurement configuration.

801. X2 SETUP REQUEST(Served Cells{[PCI, ECGI=[PLMN, CGI], TAC,Broadcasted PLMNs, EARFCN], . . . }.

Neighboring Cells{[PCI, ECGI=[PLMN, CGI], EARFCN, TAC], . . . }).

802. X2 SETUP RESPONSE(Served Cells{[PCI, ECGI=[PLMN, CGI], TAC,Broadcasted PLMNs, EARFCN], . . . }, Neighboring Cells{[PCI, ECGI=[PLMN,CGI], EARFCN, TAC], . . . }).

803. UE camps to cell in Source eNB, and attaches to PLMN=A.

803 a. As part of 3: S1AP: Initial Context Setup Request(SPID, HOrestriction list=([Serving PLMN], Equivalent PLMNs, Forbidden TAs), UERadio Capability).

805 a. RRC: SIB4 (IntraFreaBlackCellList=[PCI1, PCI2, . . . ]

805 b. RRC: SIB5 (InterFreqCarrier[{EARFCN1,InterFreqBlackCellList=[PCI1, PCI2, . . . ]}, . . . ]

806. Source eNB uses info from 802,803 a and 805 to create measurements.

807. RRC: RRCConnectionReconfiguration (measConfig=measId{[ . . . ,carrierFreq=EARFCN, blackCellsToAddMod=[PCI1, PCI2, . . . ]]}).

808. UE measures cells with PCI and carrierFreq according to 805 a, 805b, and 807.

FIG. 9 and FIG. 10 show how Handover is triggered, based on themeasurement report from the UE.

See the following example actions and messages in FIG. 9 showing thecase when the target cell PCI reported from the UE (see step 909) isunknown in the source eNB. I.e. in connected mode mobility evaluationand preparation: Target Cell PCI unknown in the source eNB.

In case of Target Cell PCI is unknown in the source eNB, currently in3GPP, the source eNB can use Configuration Transfer function (see2.1.7.4) through S1AP for TNL address discovery of the target eNB,described in 3GPP TS36.300 chapter 22.3.6.

909. RRC: MeasurementReport(measId{ . . . . PCI, . . . }, . . . ).

910. eNB selects relevant measReport uses info from 3a for HO decision.

911. HO decided, PCI unknown by eNB.

911 a. RRC: MeasurementReport(measId{ . . . , PCI, ECGI=[PLMN, CGI],TAC, PLMN-IdList, . . . }, . . . ).

811 b. Lookup eNB-ID from ECGI.

811 c. S1AP: HANDOVER REQUIRED( . . . , Target eNB-ID=[Global eNB-ID,TAI], SourceToTargetTranspCont=[ . . . , TargetCellID=ECGI, . . . ]).

See the following example actions and messages in FIG. 10 showing thecase when the target cell PCI reported from the UE (see step 1009) isknown in the source eNB. I.e. Connected mode mobility evaluation andpreparation when target Cell PCI known in the source eNB.

1009. RRC: MeasurementReport(measId{ . . . PCI, . . . }, . . . )

1010. eNB selects relevant measReport uses info from 3a for HO decision

1011. HO decided, PCI known by eNB, S1 HO (11a), X2 HO (11b), or IntraeNB HO (eNB internal signaling) is initiated.

1011 a. S1AP: HANDOVER REQUIRED( . . . , Target eNB-ID=[Global eNB-ID,TAI], SourceToTargetTranspCont=[ . . . , TargetCellID=ECGI, . . . ]).

1011 b. X2AP: HANDOVER REQUEST( . . . , TargetCellID=ECGI, . . . ])

When the handover decision is made, the reconfiguration on RAN in termsof handover between cells, including interaction with CN, will beexecuted. Examples on mobility execution is shown in FIG. 11 and FIG.12.

FIG. 11 depicts connected mode mobility execution of intra-eNB handoverwith no path switch. See the following example actions and messages inFIG. 11 showing the sequence when the handover is done between two cellswithin the same eNB, a k a intra-eNB handover. In this case, it isassumed that the transport termination point to the eNB will not bechanged.

1112. RRCConnectionReconfigurationReq(HANDOVER COMMAND).

1113. Detached from source cell, Synchronised to target cell.

1114. RRCConnectionReconfigurationComplete(HANDOVER COMPLETE).

FIG. 12 depicts connected mode mobility execution of X2 handoverexcluding path switch. See the following example actions and messages inFIG. 12 wherein the sequence for X2 handover is shown. In this case, itis assumed that the RAN endpoint will always be changed, and after thecell has been changed, data forwarding of DL data from Source eNB toTarget eNB is necessary.

1211 b. X2AP: HANDOVER REQUEST( . . . , TargetCellID=ECGI, . . . ])

1212. X2AP: HANDOVER REQUEST ACK( )

1213. RRCConnectionReconfigurationReq(HANDOVER COMMAND

1214. X2AP: STATUS TRANSFER( )

1215. Detached from source cell, Synchronised to target cell

1216. RRCConnectionReconfigurationComplete(HANDOVER COMPLETE

FIG. 13 depicts Connected mode mobility, i.e. handover, completion:X2-based handover with Serving GW relocation, related to 3GPP TS 23.401.See the following example actions and messages in FIG. 13 showing anexample of the sequence diagram for mobility completion, in this case X2based handover with serving gateway relocation.

In this case, after handover execution, the S1-U RAN endpoint willalways be changed as the eNB has been changed, and the S1-U CN (ServingGW) endpoint is relocated and the RAN/CN path will be moved to the newServing GW and the target eNB. This relocation is decided by the MME,based on network topology, i.e. the selected Serving GW serves the UE'slocation and for overlapping Serving GW service areas (Tracking areas),and load balancing between serving GW. For the tracking area of thetarget cell, this information is provided by source eNB in S1 signalPATH SWITCH REQUEST, including:

-   -   E-UTRAN CGI    -   CSG ID    -   Local Home Network ID    -   TAI

There is yet another example of mobility execution and completion, incase of S1 based handover. Same as in the previous case, the S1-U RANendpoint will always be changed as the eNB has been changed, and theS1-U CN (Serving GW) endpoint is relocated and the RAN/CN path will bemoved to the new Serving GW and the target eNB. According to 3GPPstandard, Serving GW relocation is decided by the target MME, based onthe target TAI, provided by source eNB using S1 signal HANDOVERREQUIRED, relayed through S10 with signal FORWARD RELOCATION REQUEST.

MME Triggered Serving GW Relocation

MME triggered Serving GW relocation is described in 3GPP TS 23.401,chapter 5.10.4. This procedure allows the MME to trigger Serving GWrelocation due to events other than mobility scenarios. Such scenarioexists during the establishment of a SIPTO at local network PDNconnection with stand-alone GW or during the establishment of a SIPTOabove RAN PDN connection.

FIG. 14 depicts MME triggered Serving GW relocation. See the followingexample actions and messages of this case in FIG. 14 wherein it isassumed that the S1-U RAN endpoint will be the same before and after GWrelocation.

1401. MME determines that the serving GW relocation needs to beperformed.

1402. Create Session Request.

1403 a Modify Bearer Request.

1403 b. Modify Bearer Response.

1404. Create Session Response.

1405. Bearer Modify Request/Response.

1406 a. Delete Session Request.

1406 b. Delete Session Response.

SUMMARY

It is an object of embodiments herein to provide an improved radiocommunications network.

According to a first aspect of embodiments herein, the object isachieved by a method performed by a network node for controlling whetheror not to change a transport path for a user plane session in a radiocommunications network. The path prolongs along a first part between anantenna endpoint of a network node and a Packet Processing Function,PPF, instance serving the network node and a second part between the PPFinstance and a Core Network, CN, endpoint.

The network node identifies available CN endpoints in a CN, availablePPF instances in a Radio Access Network, RAN, and of available antennaendpoints in the RAN. The available CN endpoints, available PPFinstances and available antenna endpoints are available for the userplane session and comprises a number of possible transport paths for theuser plane session.

The network node obtains characteristics of available first parts of thepossible transport paths, and characteristics of available second partsof the possible transport paths.

When the network node detects a change event related to the user planesession, the network node controls whether or not to change thetransport path to any of the a number of possible transport paths forthe user plane session based on the obtained characteristics ofavailable first parts of the transport path, and characteristics ofavailable second parts of the transport path.

According to a second aspect of embodiments herein, the object isachieved by a network node for controlling whether or not to change atransport path for a user plane session in a radio communicationsnetwork. The path is adapted to prolong along a first part between anantenna endpoint of a network node and a Packet Processing Function,PPF, instance serving the network node 111 and a second part between thePPF instance and a Core Network, CN, endpoint. The network node isconfigured to:

-   -   Identify available CN endpoints in a CN, available PPF instances        in a Radio Access Network, RAN, and of available antenna        endpoints in the RAN. The available CN endpoints, available PPF        instances and available antenna endpoints are adapted to be        available for the user plane session and comprise a number of        possible transport paths for the user plane session.    -   Obtain characteristics of available first parts of the possible        transport paths, and characteristics of available second parts        of the possible transport paths.    -   When detecting a change event related to the user plane session,        control whether or not to change the transport path to any of        the a number of possible transport paths for the user plane        session based on the obtained characteristics of available first        parts of the transport path, and characteristics of available        second parts of the transport path.

An advantage of embodiments herein is that the load of S-GW pools can bebalanced.

A further advantage of embodiments herein is that the fulfillment of theQoS end-to-end (e2e) performance can also be optimized dynamically on aUE with mobility, based on the characteristics of the available RAN/CNtransport endpoint pairs and RAN internal characteristics.

A further advantage of embodiments herein is that the fulfillment of theQoS within the mobile NW domain can be optimized based on thecharacteristics of the available RAN/CN transport endpoint pairs and RANinternal characteristics.

A further advantage of embodiments herein is that the load of RANendpoints and transport links can be balanced, it also enablespossibility to maximize the number of data streams between RAN and CNwhile fulfilling the characteristics requirement of the streams.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of embodiments herein are described in more detail withreference to attached drawings in which:

FIG. 1 is a schematic block diagram illustrating prior art.

FIG. 2 is a schematic block diagram illustrating a prior art.

FIG. 3 is a schematic block diagram illustrating a prior art.

FIG. 4 is a schematic block diagram illustrating a prior art.

FIG. 5 is a schematic block diagram illustrating a prior art.

FIG. 6 is a schematic block diagram illustrating a prior art.

FIG. 7 is a schematic block diagram illustrating a prior art.

FIG. 8 is a sequence diagram illustrating a prior art.

FIG. 9 is a sequence diagram illustrating prior art.

FIG. 10 is a sequence diagram illustrating a prior art.

FIG. 11 is a sequence diagram illustrating a prior art.

FIG. 12 is a sequence diagram illustrating a prior art.

FIG. 13 is a sequence diagram illustrating a prior art.

FIG. 14 is a sequence diagram illustrating a prior art.

FIG. 15 is a schematic block diagram depicting embodiments of a network.

FIG. 16 is a schematic block diagram illustrating a prior art.

FIG. 17 is a schematic block diagram depicting embodiments of a network.

FIG. 18 is a sequence diagram illustrating embodiments of a method.

FIG. 19 is a schematic block diagram depicting embodiments of a network.

FIG. 20 is a sequence diagram depicting embodiments of a method in aradio communications network.

FIG. 21 is a sequence diagram depicting embodiments of a method in aradio communications network.

FIG. 22 is a sequence diagram depicting embodiments of a method in aradio communications network.

FIG. 23 is a sequence diagram depicting embodiments of a method in aradio communications network.

FIG. 24 is a sequence diagram depicting embodiments of a method in aradio communications network.

FIG. 25 is a sequence diagram depicting embodiments of a method in aradio communications network.

FIG. 26 is a sequence diagram depicting embodiments of a method in aradio communications network.

FIG. 27 is a sequence diagram depicting embodiments of a method in aradio communications network.

FIG. 28 is a schematic block diagram illustrating embodiments ofscenarios in a radio communications network.

FIG. 29 is a schematic block diagram illustrating embodiments of anetwork node.

DETAILED DESCRIPTION

As part of developing embodiments herein a problem will first beidentified and discussed.

As mentioned above, according to current 3GPP standard, changes of RANendpoint is possible and mandatory only in the following occasions:

-   -   Change of eNB instance during handover.

CN endpoint is possible only in the following occasions:

-   -   Change of eNB instance during handover,    -   Change of TAI in connection to handover, which forces to a        Serving GW relocation.    -   Triggered by MME.

The decision of reselecting CN endpoint such as S-GW, is based on theTracking Area Identity (TAI) the cell is serving and/or the load of theS-GW in case multiple S-GW can be used for re-selection.

However, in e.g. a split RAN architecture, a eNB may be served by a poolof Packet Processing Functions (PPF) instances, spread over a widegeographic area. These PPF instances may be implemented as VirtualNetwork Function (VNF) or physically. Each PPF instance, also referredto as data processing instance, has capacity to serve a number of usersessions, and will have its own RAN endpoint. This pool of PPF instancesmay also serve multiple eNBs. This new architecture will cause multipleendpoints in RAN and CN.

An example of multiple endpoints in both RAN and CN is illustrated inFIG. 15, On the CN side, S-GW1 and S-GW2 may serve a certain geographicarea and are located in different locations. On RAN side, a pool of dataPPF instances PPF1, PPF2 and PPF3 are serving eNBs in the same area,where PPF1 and PPF2 serve eNB1, while PPF2 and PPF3 serve eNB2. eNB1 andeNB2 will serve their respective areas and/or frequencies.

For each link between (1) an eNB antenna endpoint—RAN endpoint such as aPPF instance, and (2) a RAN endpoint such as a PPF instance—CN endpointwill have its own characteristics in terms of e.g. latency, and in caseof RAN-CN endpoint pairs, also max bitrate.

FIG. 15 depicts an example on multi endpoint on both CN and RAN.

As the figure shows, a user data path between a UE and a CN, when the UEis in different locations, can be connected through several antennaendpoint-PPF instance-CN endpoint combinations, resulting differentcharacteristics. The table below shows the best antenna-RAN-CN-endpointcombinations.

TABLE 1 Antenna-RAN-CN endpoints combination for best characteristics UELOCATION LOWEST LATENCY HIGHEST BANDWIDTH A PPF1 - S-GW1 PPF2 - S-GW1 BPPF2 - S-GW2 PPF2 - S-GW1 C PPF2 - S-GW2 PPF2 - S-GW1 D PPF3 - S-GW2PPF2 - S-GW1

This table shows that in case for best latency characteristics, a pathswitch should be done on each location change except during handoverbetween eNB1 and eNB2 (A to B, and C to D), while for best bandwidth, nopath switch shall be done during any location change, which is not inline with the current standard.

-   -   Change of endpoint pairs during intra eNB handover (A to B and C        to D)    -   No change of endpoint during X2/S1 handover (B to C)

So as a consequence of the problem is that the decision of path switchof a user data path is highly depending on what characteristics isneeded for the user data (in the example above is lowest latency versushighest bandwidth), mobility of the user and change of characteristicson CN endpoints, PPF instances, antenna endpoints and the paths inbetween them.

Embodiments herein refer to an S1 user plane selection in case of achange event related to the user plane session such as e.g. a handover,and some embodiments herein may be implemented as a Traffic HandlingFunction.

In order to select the optimum path between the transport endpointsbetween the CN and the RAN e.g. in connection to cell change, thefollowing actions may be taken:

1) Definition of characteristics between the cell/antenna endpoint andthe data processing instances, also referred to as the PPF instances,and for the PPF instances and the CN endpoints used for controlling theRAN/CN endpoint pair selection decision.

2) Mechanism for RAN to distribute the characteristics between theantenna endpoint and the PPF instance and the characteristics betweenthe PPF instances and the CN endpoint for RAN/CN endpoint pair selectiondecision.

3) Mechanism for RAN to control e.g. by requesting and deciding whetherto change or not change a transport path such as endpoint pairs for auser plane session (in any combinations) in connection to any typechange event related to the ongoing user plane session. Which changeevent may be related to cell changes e.g. intra-eNB handover, inter-eNBX2 handover and inter-eNB S1 handover or anytime due to e.g. loadbalancing of RAN endpoints and/or MME decided S-GW relocation.

Observe that although LTE terminology is used herein, embodiments hereinmay also be used for 5G. Also type of cell changes is not only limitedto handover, but also including e.g. carrier aggregation or dualconnectivity cases.

Observe that different methods are described such as “distributionduring association between nodes” and “distribution during on demandoccasion”.

It should be noted that the term “endpoint” when used herein means“transport endpoint” and the wordings “endpoint” and “transportendpoint” may be used interchangeably.

The overall principles of embodiments herein would work for both anLTE-like architecture and a new architecture based on an evolution ofthe S1 interface.

A management system wherein some embodiments herein may be implementedis shown in FIG. 16. The Node Elements (NE), also referred to as eNodeB,are managed by a Domain Manager (DM), also referred to as the operationand support system (OSS). A DM may further be managed by a NetworkManager (NM). Two NEs are interfaced by X2, whereas the interfacebetween two DMs is referred to as Interface (Itf)-Peer to Peer (P2P).The management system may configure the NEs, as well as receiveobservations associated to features in the network elements. Forexample, DM observes and configures NEs, while NM observes andconfigures DM, as well as NE via DM.

By means of configuration via the DM, NM and related interfaces,functions over the X2 and S1 interfaces may be carried out in acoordinated way throughout the RAN, eventually involving the CoreNetwork, i.e. MME and S-GWs.

Embodiments herein relate to radio communications networks in general. Aradio communications network 100 as schematically illustrated in FIG.17. For example, embodiments herein may be implemented in the radiocommunications network 100. The radio communications network 100 may bea cellular communications network. Further, the radio communicationsnetwork 100 may be an LTE network, a 5G network, a WCDMA network, an GSMnetwork, any 3GPP cellular network, Wimax, or any other radiocommunications network or system.

The wireless communication network 100 comprises one or more RANs, e.g.a RAN 102, and one or more CNs, e.g. a CN 104. The wirelesscommunication network 100 may use a number of different technologies,such as Wi-Fi, LTE, LTE-Advanced, 5G, WCDMA, Global System for Mobilecommunications/enhanced Data rate for GSM Evolution (GSM/EDGE), WiMax,or UMB, just to mention a few possible implementations. Embodimentsherein relate to recent technology trends that are of particularinterest in a 5G context, however, embodiments are also applicable infurther development of the existing wireless communication systems suchas e.g. WCDMA and LTE.

RAN nodes such as at least a radio network node 111, also referred to asany of the source radio network node 111 and the target radio networknode 111 in some scenarios, and a radio network node 112, also referredto as the second radio network node 112, the source radio network node112 or the target network node 112 in some scenarios, operate in the RAN102 in the radio communications network 100. The one or more RAN nodessuch as the Radio network node 111 may be a transmission and receptionpoint e.g. a radio access network node such as a Wireless Local AreaNetwork (WLAN) access point or an Access Point Station (AP STA), anaccess controller, a base station, e.g. a radio base station such as aNodeB, an evolved Node B (eNB, eNode B), a base transceiver station, aradio remote unit, an Access Point Base Station, a base station router,a transmission arrangement of a radio base station, a stand-alone accesspoint or any other network unit capable of communicating with a wirelessdevice within the service area served by the radio network node 111depending e.g. on the first radio access technology and terminologyused. The radio network node 111 and the radio network node 112 may bereferred to as a serving radio network nodes and communicate with awireless device 120 with Downlink (DL) transmissions to a wirelessdevice 120 and Uplink (UL) transmissions from the wireless device 120.Other examples of the radio network node 111 and the radio network node112 are Multi-Standard Radio (MSR) nodes such as MSR BS, networkcontrollers, Radio Network Controllers (RNCs), Base Station Controllers(BSCs), relays, donor nodes controlling relay, Base Transceiver Stations(BTSs), Access Points (APs), transmission points, transmission nodes,Remote Radio Units (RRUs), Remote Radio Heads (RRHs), nodes inDistributed Antenna System (DAS) etc.

The one or more RAN nodes such as the radio network node 111 and theradio network node 112 each provides radio coverage via one or moreantenna endpoints over a geographical area, which may also be referredto as a cell, a cluster, a beam or a beam group, of a Radio AccessTechnology (RAT), such as 5G, LTE, Wi-Fi or similar.

The radio network node 111 comprises two available antenna endpoints1111, 1112 also referred to as eNB antenna points and RAN transportendpoints.

The radio network node 112 comprises two available antenna endpoints1211, 1122 also referred to as RAN transport endpoints.

An antenna endpoint is a point where antenna data and/or cell data forall the users associated to the antenna/cell is being processed. Notethat the antenna endpoint may also be referred to as a cell endpoint.

However, it should be noted that more than two radio network nodes (notshown) may operate in the RAN 102 according to some embodiments.Further, the radio network nodes 111, 112 may each comprise more or lessthan two RAN transport endpoints.

Each radio network node 111, 112 is served by one or more PPF instancesPPF1 171, PPF2 172, PPF3 173. The radio network node 111 is served byPPF instance PPF1 171 and PPF2 172.

The radio network node 112 is served by PPF instance PPF2 172 and PPF3173.

For each PPF instance, there will be one or several RAN endpoints. Inthis example PPF1 171 contains RAN endpoint 1711, PPF2 172 contains RANendpoints 1721 and 1722, and PPF3 173 contains RAN endpoints 1731.Observe that same RAN endpoint may be used by several Radio networknodes, e.g. in this example RAN endpoints 1721 and 1722 may be used byboth Radio network nodes 111 and 112.

At least one CN node 130 may be configured to operating and/or comprisedin the CN 104.

The at least one CN node 130 may e.g. be a Mobility Management Entity(MME) such as MME1 and MME2, or any other core network node. In someembodiments, the one or more CN node 130 interface towards the PPFinstances PPF1, PPF2, PPF2.

Gateway nodes such as a first gateway (GW) node 141 and a second GW node142 may be operating and/or comprised in the CN 104. The first GW node141 and the second GW node 142 are configured to operate in the radiocommunications network 100, e.g. in the CN 104 and communicate with theCN node 130.

The first GW node 141 and second GW node 142 may e.g. be a servinggateway node (S-GW) in an LTE network or a user plane GW node in 5Gnetwork. The first GW node 141 comprises two available CN transportendpoints, referred to as CN endpoints 1411, 1412 herein. The second GWnode 142 comprises one available CN transport endpoint referred to as CNendpoint 1421. Thus in FIG. 17, the CN 104 comprises three CN endpoints1411, 1412, 142. However, it should be noted that the CN 104 maycomprise more than three CN endpoints and more than two GW nodes.

In the wireless communication network 100, wireless devices e.g. awireless device 120 such as a mobile station, a non-Access Point(non-AP) STA, a STA, a user equipment and/or a wireless terminals,communicate via one or more RANs such as the RAN 102, to one or more CNssuch as the CN 104. Thus, the wireless device 120 is operating in theradio communications network 100.

It should be understood by the skilled in the art that “wireless device”is a non-limiting term which means any terminal, communications device,wireless communication terminal, user equipment, Machine-TypeCommunication (MTC) device, Device-to-Device (D2D) terminal, or nodee.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets,an Internet-of-Things (IoT) device, e.g. a Cellular IoT (CIoT) device oreven a small base station communicating within a service area.

In this disclosure the terms communications device, terminal, wirelessdevice and UE are used interchangeably. Please note the term userequipment used in this document also covers other wireless devices suchas Machine-to-Machine (M2M) devices, even though they do not have anyuser.

The wireless communication network 100 may further comprise a database150. Identifiers of available CN endpoints 1411, 1412, 1421, RANendpoints 1711, 1721, 1722, 1731, and antenna endpoints 1111, 1112,1121, 1122 may be stored in the database 150. The database 150 may beaccessible both from RAN nodes such as any of the radio network node 111and the radio network node 112, from CN nodes such as the core networknode 130, and the GW nodes 141 and 142.

Some actions in methods herein may performed by any of the radio networknode 111, the second radio network node 112 core network node 130, theseare therefore in a general term referred to as the network node 111,112, 130. As an alternative, any distributed Network Node (NN) andfunctionality, e.g. comprised in a cloud 160 may be used for performingthese actions.

According to an example scenario in some embodiments herein, thefollowing may be comprised:

-   -   A RAN node such as the radio network node 111 and the radio        network node 112 may comprise multiple antenna endpoints 1111,        1112, 1121, 1122.

A RAN node such as the radio network node 111 and the radio network node112 may be served by one or more PPF instances PPF1 171, PPF2 172, PPF3173 with RAN endpoints 1711, 1721, 1722, 1731.

-   -   A CN such as the CN 104 may comprise one or multiple transport        endpoints such as CN endpoints 1411, 1412, and 1421.

Embodiments herein relate to methods performed by the radio network node111 for controlling whether or not to change a transport path for a userplane session in a radio communications network 100. The user planesession may be used by the wireless device 120 to for transmitting datawithin the radio communications network 100.

The path of a user plane session prolongs along: A first part between anantenna endpoint of a network node 111 and the Packet ProcessingFunction, PPF1 and PPF2, with its RAN endpoint 1711, 1721, 1722,instance 1111, 1112 serving the network node 111 and a second partbetween the PPF instance PPF1, PPF2, with RAN endpoint 1711, 1721, 1722and a Core Network, CN, endpoint 1411, 1412, 1421.

-   -   The available CN endpoints 1411, 1412, 1421, available PPF        instances 171, 172, 173 with RAN endpoints 1711, 1721, 1722,        1731 and available antenna endpoints 1111, 1112, 1121, 1122 are        available for the user plane session and comprises a number of        possible transport paths for the user plane session.    -   Between each available CN endpoints 1411, 1412, 1421, and        available antenna endpoints 1111, 1112, 1121, 1122, via the        available PPF instances 171, 172 with RAN endpoints 1711, 1721,        1722, 1731, also referred to as path, there is a channel with        certain characteristics, such as e.g. delay and total Bandwidth        (BW).    -   E.g. a UE such as the wireless device 120 requires a session to        be set up for incoming data communication or outgoing data        communication. Therefore, a number of data streams needs to be        established between the RAN 102 and the CN 104 to be used for        the required session, with certain characteristics requirements        such as e.g. max delay and bandwidth.    -   For each data stream, one RAN—CN transport endpoint pair via an        antenna instance, =path, is selected in order to fulfill the        data stream characteristics requirement, and maximize the number        of data streams between the RAN 102 and the CN 104 fulfilling        the characteristics requirement of the streams.

Example embodiments of a method performed by the network node 111, 112,130 such as any of the radio network node 111, the second radio networknode 112 e.g. a target eNB, or the CN node 130, for controlling whetheror not to change a transport path for a user plane session in the radiocommunications network 100 will now be described with reference to aflowchart depicted in FIG. 18. The method will first be described in aview seen from the core network node 130 together with FIG. 18, followedmore detailed explanations and examples.

In case of a handover event, the radio network node performing themethod may be any one of a target radio network node and a source radionetwork node.

As mentioned above, the path prolongs along: A first part between anantenna endpoint of a network node 111 and a PPF, instance 1111, 1112serving the network node 111 and a second part between the PPF instanceand a Core Network, CN, endpoint.

The method comprises the following actions, which actions may be takenin any suitable order.

To be able to control such as obtain a suitable transport path for theuser plane session according to embodiments herein, available antennaendpoints and PPFs at the RAN 102 and CN endpoints at the CN 104 shallfirst be identified. It is preferred that the CN 104 and the RAN 102 areaware of which transport endpoints and antenna instances that areavailable on the remote side for a user plane interface, also known asS1-U for LTE and NG3 for 5G, in order to have a possibility to select atransport path with the best characteristics for an upcoming user planesession.

Thus, the network node 111, 112, 130 identifies available CN endpoints1411, 1412, 1421 in the CN 104, available PPF instances PPF1, PPF2, PPF3also referred to as PPF1 171, PPF2 172, PPF3 173, which may comprise RANendpoints 1711, 1721, 1722, 1731 in the RAN 102, and of availableantenna endpoints 1111, 1112, 1121, 1122 in the RAN 102.

The available CN endpoints 1411, 1412, 1421, available PPF instances171, 172,173 e.g. with RAN endpoints 1711, 1721, 1722, 1731 andavailable antenna endpoints 1111, 1112, 1121, 1122 are available for theuser plane session and comprises a number of possible transport pathsfor the user plane session.

Action 1801

Thus, the network node 111, 112, 130 identifies, available CN endpoints1411, 1412, 1421 in the CN 104. According to the example shown in FIG.17, the CN 104 comprises three CN endpoints 1411, 1412, 1421. In thisexample the core network node 130 may obtain three identifiers ofavailable CN endpoints 1411, 1412, 1421 which may be transferred to thenetwork node 111, 112, 130 enabling the network node 111, 112, 130 toidentify the available CN endpoints 1411, 1412, 1421 in the CN 104.Examples of type of identifiers may e.g. be a transport layer addressaccording to 3GPP 36.413, an IP address for the endpoint, a newidentifier created for this purpose.

Action 1802

The network node 111, 112, 130 further identifies available PPFinstances PPF1 171, PPF2 172 and PPF3 173 e.g. with their RAN endpoints1711, 1721, 1722, 1731 in the RAN 102. According to the example shown inFIG. 17, the RAN 104 comprises three PPF instances PPF1, PPF2 and PPF3.In this example the radio network node 111 may identify the three PPFinstances PPF1, PPF2 and PPF3 and their RAN endpoints by e.g. atransport layer address according to 3GPP 36.413, an IP address for theendpoint, a new identifier created for this purpose.

Action 1803

The network node 111, 112, 130 further identifies available antennaendpoints 1111, 1112, 1121, 1122 in the RAN 102. According to theexample shown in FIG. 17, the radio network node 111 comprises twoavailable antenna endpoints 1111, 1112, and the radio network node 112comprises two available antenna endpoints 1121, 1122. This means the RAN102 comprises four available antenna endpoints 1111, 1112, 1121, 1122.In this example the network node 111 may identify the available antennaendpoints 1111, 1112, 1121, 1122 by e.g. E-UTRAN Cell Global Identity(E-CGI), internal IP address connected to the E-CGI, or new identifieridentifying the antenna point/cell.

To be able to select such as control a suitable transport path for theuser plane session according to embodiments herein, characteristics ofthe first part and the second part of available transport paths will beobtained and e.g. be investigated and compared with a current transportpath of the user plane session.

Action 1804

Thus the radio network node 111 obtains characteristics of the availablefirst parts of the possible transport paths.

Action 1805

The radio network node 111 further obtains characteristics of theavailable second parts of the possible transport paths.

In some embodiments, the characteristics of the available first parts ofthe transport path, and the characteristics of the available secondparts of the transport path are obtained in advance of any change eventrelated to the user plane session.

In some alternative embodiments, the characteristics of the availablefirst parts of the transport path, and the characteristics of theavailable second parts of the transport path are obtained during thedetected change event related to the user plane session.

The characteristics of any one or more out of: the available first partsof the transport path and the available second parts of the transportmay relate to any one or more out of: latency of said first part and/orsecond part, obtainable bandwidth of said first part and/or second part,number of active sessions in said first part and/or second part,bandwidth usage of said first part and/or second part, monetarytransmission cost of said first part and/or second part, and anyvariables which provides preference of said first part and/or secondpart.

In some alternative embodiments, the characteristics of the availablefirst parts of the possible transport paths, and characteristics of theavailable second parts of the possible transport paths, are obtained inany one out of:

A static configuration, wherein the characteristics are stored in a database 150 when a new available CN endpoint, a new available PPF instancePPF1, PPF2, PPF3 with their RAN endpoints and/or a new available antennaendpoint is introduced, and

an autonomous configuration, wherein the characteristics are obtained by

(a) obtaining measurements of the respective available first part andsecond part of the number of possible transport paths,

b) matching identities related to the characteristics of the respectiveavailable CN endpoints 1411, 1412, 1421, available PPF instances PPF1,PPF2, PPF3 and/or available antenna endpoints 1111, 1112, 1121, 1122.

In the static configuration, the characteristics may be stored in thedata base 150 when a new available CN endpoint 1411, 1412, 1421, a newavailable PPF instance PPF1, PPF2, PPF3 with their RAN endpoints, and/orantenna instance 1111, 1112, 1121, 1122 is introduced.

In the autonomous configuration, the characteristics may be obtained by

(a) obtaining measurements of the respective transport path of thenumber of possible paths, and/or

(b) matching identities related to the characteristics of the respectiveavailable first and second part of the path.

The obtaining of the characteristics according to the staticconfiguration and the autonomous configuration will be described more indetail below.

Action 1806

When detecting a change event related to the user plane session, theradio network node 111 or e.g. CN node 130 controls whether or not tochange the transport path to any of the a number of possible transportpaths for the user plane session based on the obtained characteristicsof available first parts of the transport path, and characteristics ofavailable second parts of the transport path. The obtainedcharacteristics of the first part and the second part of the availabletransport paths are e.g. investigated and compared with the currentongoing transport path of the user plane session and/or retrievedconfiguration of the transport paths. In this way the radio network node111 and/or the CN node 130 can control that the most suitable transportpath for the user plane session is selected for example in occasion ofan event such as a hand over scenario from the network node 111 to thesecond network node 112.

Controlling when used here means controlling the path selection duringhandover or path switch procedure.

In some embodiments, the characteristics of the available first parts ofthe transport path, and the characteristics of the available secondparts of the transport relate to latency. In these embodiments, theradio network node 111 and/or CN node 130 may control whether or not tochange the transport path to any of the a number of possible transportpaths for the user plane session based on selecting the transport pathwith lowest delay.

In some embodiments, the characteristics of the available first parts ofthe transport path, and the characteristics of the available secondparts of the transport relate to bandwidth. In these embodiments theradio network node 111 and/or CN node 130 may control whether or not tochange the transport path to any of the a number of possible transportpaths for the user plane session based on selecting the transport pathwith broadest bandwidth.

In some embodiments, the characteristics of the available first parts ofthe transport path, and characteristics of the available second parts ofthe transport relate to latency and bandwidth. In these embodiments theradio network node 111 and/or CN node 130 may control whether or not tochange the transport path to any of the a number of possible transportpaths for the user plane session based on selecting a transport pathwith lowest delay and broadest bandwidth.

The detected change event related to the user plane session may compriseany one or more out of: A handover decision, adding a carrier related tocarrier aggregation and setting up or changing a dual connectivity, achange of PPF instance PPF1, PPF2, PPF3 initiated by the radio networknode 111 due to changes of characteristics, a change of PPF instancePPF1, PPF2, PPF3 initiated by a core network node 130, such as e.g. anMME, due to changes of characteristics. Those changes of characteristicsmay be caused by e.g. load balancing of PPF pool, error in PPF/S1-U,change of load on some users in the system etc.

Embodiments herein will now be further described and exemplified. Thetext below is applicable to and may be combined with any suitableembodiment described above. It should be noted that in the examplesbelow the radio network node 111 is referred to as the eNB or the sourceeNB, the second radio network node 112 is referred to as the neighboringeNB or target eNB, the wireless device 120 is referred to as the UE, andthe CN node 130 is referred to as the MME or MME1 in the examples below.

Embodiments herein may comprise:

1) A definition of characteristics between an available antenna endpointand an available PPF instance.

2) A characteristics distribution method to the related RAN and CNnodes, and mechanism for controlling endpoint pair changes such as pathchanges of the transport path to any of the a number of possibletransport paths for the user plane session, e.g. during cell changesand/or other occasions according to an alternative comprisingcharacteristics distribution prior change of endpoint pairs.

-   -   a. Characteristics distribution during radio network node setup        111, 112 such as eNB setup, centralized approach.    -   b. Characteristics distribution during association between        nodes, distributed approach.    -   c. Change of endpoint pairs occasions, examples.

3) Characteristics distribution method to the related RAN and CN nodes,and mechanism for controlling endpoint pair changes such as path changesof the transport path to any of the a number of possible transport pathsfor the user plane session, e.g. during cell changes and/or otheroccasions according to an alternative comprising characteristicsdistribution during demanding occasion.

-   -   a. Characteristics distribution principle.    -   b. Change of endpoint pairs occasions (including characteristics        distribution), examples

1) Definition of Characteristics Between an Antenna Endpoint and a PPFInstance

Characteristics between an available antenna endpoint and an availablePPF instance may comprise of the following parts:

-   -   Identification of the available antenna endpoints 1111, 1112,        1121, 1122.    -   Identification of the available PPF instances PPF1, PPF2, PPF3        with their RAN endpoints 1711, 1721, 1722, 1731.    -   Characteristics information between the available antenna        endpoints 1111, 1112, 1121, 1122 and the available PPF instances        PPF1, PPF2, PPF3. I.e. the characteristics of the second parts        of the available transport paths.

For identifying an available antenna endpoint 1111, 1112, 1121, 1122, incase of LTE, an E-UTRAN Cell Global ID (ECGI) may be used. For 5G, asthere may be multiple antenna endpoints per System Area, ECGI may bereplaced by e.g. an identity for identifying a unique antenna endpointand/or System Area in a certain radio network node 111 such as whenbeing a gNB.

For identifying an available PPF instance PPF1, PPF2, PPF3 and theircorresponding RAN endpoints, a transport layer address InformationElement (IE) in S1AP, or other new identity may be used.

Characteristics information between the available antenna endpoints1111, 1112, 1121, 1122 and the available PPF instances PPF1, PPF2, PPF3with their corresponding RAN endpoints may be any combinations of thefollowing example attributes: latency of said first part and/or secondpart, obtainable bandwidth of said first part and/or second part, numberof active sessions in said first part and/or second part, bandwidthusage of said first part and/or second part, monetary transmission costof said first part and/or second part, and any variables which providespreference of said first part and/or second part. E.g. any combinationof latency between antenna endpoint and PPF instance, obtainablebandwidth between antenna endpoint and PPF instance, number of activeusers and/or sessions between antenna endpoint and PPF instance,bandwidth usage between antenna endpoint and PPF instance, transmissioncost (monetary) between antenna endpoint and PPF instance and othervariables which provides preference between antenna endpoint and PPFinstance.

Examples on the format of the characteristics may be: Triplet: ECGI-RANendpoint ID—transmission cost, and/or ECGI—priority list of RAN endpointID.

2) Characteristics Distribution Method to the Related RAN and CN Nodes,and Mechanism for Controlling Endpoint Pair Changes During Cell Changesand/or Other Occasions—Characteristics Distribution Prior Change ofEndpoint Pairs

Obtaining Characteristics

This part is related to Action 1804 and 1805 described above.

Examples of Static Configuration

When a new available antenna endpoints 1111, 1112, 1121, 1122, PPFinstance or CN endpoint 1411, 1412, 1421 is introduced, thecharacteristics value, e.g. “path delay” and “path bandwidth” betweenthe new available antenna endpoints 1111, 1112, 1121, 1122, PPF instanceor CN endpoint 1411, 1412, 1421, and the existing remote endpoints maybe set manually, and these values may be stored in the database 150 orin the core network node 130 such as the MME, and eventually in theradio network node 111 for the path selection and/or decision action.

The distribution of this static configuration may be performed throughthe RAN↔CN control interface e.g. in LTE, during a eNB/MME configurationupdate procedure in S1AP, or outbound through e.g. O&M interface.

Examples of Autonomous Determination

In autonomous determination, the characteristics of the endpoint pairsmay be determined and/or obtained by the Radio network node 111 and/orCN node such as the gateway nodes 141, 142 e.g. by measurements and/orIdentity matching.

Obtaining the characteristics by measurements, may be performed by likeRound Trip Time (RTT) measurement by using IP ping or other test tools,and for bandwidth measurement by e.g. continuously or periodicallyrunning a Two-way Active Measurement Protocol (TWAMP) tests.

Obtaining the characteristics by identity matching, e.g. each datacenter has assigned with a unique identifier or an Area Identifier(AreaId). A data center here refers to a facility in a physical locationcomposed of networked computers and storage that businesses or otherorganizations use to organize, process, store and disseminate largeamounts of data. When each available RAN endpoint 1711, 1721, 1722,1731, or CN endpoint 1411, 1412, 1421 is created in a data center, adata center identifier is known by the available RAN endpoint 1711,1721, 1722, 1731, or CN endpoint 1411, 1412, 1421 in the Radio networknode 111 and/or gateway node 141, 142. An endpoint pair with the samedata center identifier is recognized having shorter delay than pair withdifferent data center identifiers. In case of using measurement, theresults may be stored in the database 150 or in the core network node130 such as in the MME, and eventually in the Radio network node 111 forthe endpoint pair selection Action.

The distribution of the determination results may be performed with thefollowing example methods:

(a) Continuously through the RAN↔CN control interface e.g. in LTEeNB/MME configuration update procedure in S1AP may be used.

(b) Continuously through outbound such as O&M interface,

(c) During runtime when the RAN↔CN user plane needs to be setup throughRAN↔CN control signaling, e.g. in LTE during E-RAB setup, E-RAB modify,Initial context setup, and/or handover request procedure in S1AP.

Characteristics Distribution During Radio Network Node Setup Such as eNBSetup, in a Centralized Approach.

In this approach, the characteristics of the first part and second partof the available transport paths will be stored in a centralized node,e.g. in the Data Base (DB) 150. The DB 150 may be accessible both fromRAN nodes such as the network node 111 and from CN nodes such as the CNnode 130. The centralized DB 150 may be collocated with other nodes, andmay also be distributed for scalability and redundancy reasons.

Each time when the following configuration in an eNB such as the networknode 111 is changed, the corresponding characteristics shall beregistered to the centralized DB 150. I.e. the RAN/CN nodes registersthe new endpoint in the DB for later discovery.

-   -   Add/remove of an antenna endpoint    -   Add/remove of a PPF instance    -   Add/removal of a path between an antenna endpoint and a PPF        instance.    -   Changes of characteristics in an antenna endpoint and/or a PPF        instance.

In LTE, the changes may be informed to the CN 104 through an MME such asthe CN 130 by a new IE in S1 Setup procedure and/or eNB configurationupdate procedure and that the MME updates the DB 150. Anotheralternative is that the DB 150 is updated using other channels, e.g.using Operation and Maintenance (O&M).

Characteristics Distribution During Association Between Nodes, in aDistributed Approach.

In this approach, only necessary characteristics needed for the radionode 111 and the CN node 130 will be stored locally such as in an LTEeNB and MME. The first distribution of information between the radionode 111 and the CN node 130 is done during a first association, changesof association between these nodes or changes on characteristics of theradio node 111 the PPF instances and the CN node 130. Examples may besetup of S1/X2 interfaces, detection of neighboring cell relationshipetc. The distribution of characteristics may be done through thefollowing interfaces and procedures.

-   -   S1AP: S1 Setup Procedure    -   S1AP: eNB Configuration Update    -   X2AP: X2 Setup Procedure    -   X2AP: eNB Configuration Update    -   S1AP: eNB Configuration Transfer    -   S1AP: MME Configuration Transfer    -   S10: Configuration Transfer Tunnel

The basic principle for the distribution may e.g. be as follows:

When a eNB such as the network node 111 is connected to an MME such asthe CN node 130, the eNB should transfer the available characteristicsfor the eNB, i.e. its own and it neighbor eNB's antenna endpoints andPPF instances through S1AP: S1 Setup Procedure.

When the eNB detects a new cell which is unknown for the eNB, the eNBand the new neighbor eNB such as the second radio network node 112serving the new cell may exchange their characteristics through S1AP:eNB Configuration Transfer, S1AP: MME Configuration Transfer and in somecases also S10: Configuration Transfer Tunnel.

When the eNB sets up an X2 connection to a neighbor eNB as describedabove, the eNB and the new neighbor eNB may exchange theircharacteristics through X2AP: X2 Setup procedure.

When the following configuration in an eNB is changed:

-   -   Add and/or remove of an antenna endpoint.    -   Add and/or remove of a PPF instance.    -   Add and/or removal of a path between an antenna endpoint and an        PPF instance.    -   Changes of characteristics of the path between an antenna        endpoint and an PPF instance.

The new and/or removed characteristics may be distributed using thefollowing procedures:

-   -   To the MME using S1AP: eNB Configuration Update    -   To all neighbor eNBs with X2 connection using S1AP: eNB        Configuration Update    -   To all neighbor eNBs without X2 connection using S1AP: eNB        Configuration Transfer, where MME will forward it using S1AP:        MME Configuration Transfer if MME has S1AP connection to the        neighboring eNB, or using S10: Configuration Transfer Tunnel to        the MME which has connection to the neighboring eNB.

When the eNB receives characteristics from the neighboring eNB throughS1AP: MME Configuration Transfer. The eNB shall send this update to itsMMEs using S1AP: eNB Configuration Update.

An example on how the characteristics are distributed with this approachin an example network is described in FIG. 19:

Pre-requisite: MME1 such as the CN node 130 and MME2 are setup and isconnected through an S10 interface.

Step 1: eNB1 such as the radio network node 111 connects to MME1.

-   -   Characteristics from eNB1 will be sent to MME1 through S1 Setup        procedure.

Step 2: eNB2 such as the second radio network node 112 connects to MME1

-   -   Characteristics from eNB2 will be sent to MME1 through S1 Setup        procedure.

Step 3: eNB3 connects to MME2

-   -   Characteristics from eNB3 will be sent to MME2 through S1 Setup        procedure.

Step 4: A UE such as the wireless device 120 should be handover from acell provided by eNB1 to a cell provided by eNB2 for the first time.eNB1 and eNB2 are unknown for each other in this example scenario.Besides a normal handover for the UE they should also transfer thecharacteristics with each other by:

-   -   eNB1 and eNB2 exchange their characteristics with each other,        with one of the following methods:    -   Using S1AP: eNB Configuration Transfer and S1AP: MME        Configuration Transfer.    -   Using X2AP:X2 Setup procedure.

Step 5: An UE should be handover from a cell from eNB2 to a cell fromeNB3 (eNB2 and eNB3 are unknown for each other) for the first time.Besides a normal handover for the UE they should also transfer thecharacteristics with each other by.

-   -   eNB2 and eNB3 exchange their characteristics with each other by        using S1AP: eNB Configuration Transfer, S10: Configuration        Transfer Tunnel, and S1AP: MME Configuration Transfer.    -   eNB2 distributes the characteristics on eNB3 to MME1 using S1AP:        eNB Configuration Update.    -   eNB3 distributes the characteristics on eNB2 to MME2 using S1AP:        eNB Configuration Update.

Step 6: Changes on characteristics occur on eNB1.

-   -   eNB1 distributes the changes to MME1 using S1AP: eNB        Configuration Update.    -   eNB1 distributes the changes to eNB2 using X2AP: eNB        Configuration Update.

Step 7: Changes on characteristics occur on eNB3.

-   -   eNB3 distributes the changes to MME2 using S1AP: eNB        Configuration Update    -   eNB3 distributes the changes to eNB2 using S1AP: eNB        Configuration Transfer, S10: Configuration Transfer Tunnel, and        S1AP: MME Configuration Transfer.    -   eNB2 distributes the characteristics changes on eNB3 to MME1        using S1AP: eNB Configuration Update.

Examples of Occasions for Change of Endpoint Pairs for the TransportPath.

Intra eNB Handover

As the characteristics are known within the same eNB, the eNB may byitself decide if change of PPF instance is needed or not. In case changeof PPF is needed, the eNB can setup a data forwarding between PPFinstance during handover execution phase and issue a path switchprocedure during handover completion phase as described in FIG. 20.

An example on Intra eNB handover, where change of PPF instance isdecided and requested by the eNB and accepted by the MME, with noendpoint change on CN side, is shown in FIG. 20. The new sequencescompare to the legacy are marked with dotted lines in the Figure.

See the following example actions and messages in FIG. 20:

2012. eNB decides to change PPF instance in connection to intra eNBHandOver (HO).

2013. RRCConnectionReconfigurationReq(HANDOVER COMMAND).

2014. eNB forwards DL data from source PPF instance to target PPFinstance.

2015. Detached from source cellSynchronised to target cell.

2016. RRCConnectionReconfigurationComplete(HANDOVER COMPLETE)

2017. Path Switch Request.

2018. MME decides no change on CN endpoint 1411, 1412, 1421 such as SGWendpoint and redirect DL data from SGW to Target PPF instance

2019. Path Switch Request Acknowkedge.

2020. The eNB removes unused resource and DL forwarding path.

Inter eNB X2 Handover

As the characteristics of the neighboring eNB is already known, alreadydistributed during setup or obtainable via external DB 150, if PPFinstance change is necessary, a normal X2 handover will be executed. Ifthe PPF instance changes is not necessary, the source eNB shall in X2:Handover Request notify the target eNB that no PPF instance change isneeded, and no path switch procedure shall be executed. FIG. 21 showsthe sequence of X2 handover with no PPF change.

The new sequences (compared to the legacy sequences) are marked withdotted lines and underlined text in the Figure.

See the following example actions and messages in FIG. 21 regardingInter-eNB X2 handover where the neighbour characteristics are known byeNB prior handover occasion, no PPF change needed:

2111 b. X2AP: HANDOVER REQUEST( . . . , TargetCellID=ECGI, . . . ],CommonPPFId)

2111 z. Target eNB reuse the common PPFresource.

2112. X2AP: HANDOVER REQUEST ACK.

2113. RRCConnectionReconfigurationReq(HANDOVER COMMAND).

2114. Source eNB notify PPF to redirect DL traffic to target eNB.

2115. Detached from source cell Synchronised to target cell.

2116. RRCConnectionReconfigurationComplete(HANDOVER COMPLETE).

Inter eNB S1 Handover

As the characteristics of the neighboring eNB is already known, alreadydistributed during setup or obtainable e.g. via external DB 150, if PPFinstance change is necessary, a normal S1 handover will be executed. IfPPF instance change is not necessary, the source eNB shall in S1AP:Handover Required/Handover Request message notify the target eNB and MMEthat no PPF instance change is needed, and no path switch procedure willbe executed.

See the following example actions and messages in FIG. 22 regardingInter-eNB S1 handover, neighbor characteristics known by eNB priorhandover occasion, no PPF change and no SGW change needed. The newsequences compare to the legacy are marked with dotted lines andunderlined text in the Figure.

2201. S1AP: HANDOVER REQUIRED( . . . , TargetCellID=ECGI, . . . ,CommonPPFId).

2202. S10: Forward Relocation Request( . . . , TargetCellID=ECGI, . . ., CommonPPFId)

2205. S1AP: HANDOVER REQUEST( . . . , TargetCellID=ECGI, . . . ,CommonPPFId).

220X. Target eNB reuse the common PPF instance resource.

2205 a. S1AP: HANDOVER REQUEST ACK.

2207. S10: Forward Relocation Response.

2209. S1AP: HANDOVER COMMAND.

2209 a. RRCConnectionReconfigurationReq(HANDOVER COMMAND).

2209 b. Source eNB notify PPF to redirect DL traffic to target eNB.

2209 c. Detached from source cell Synchronised to target cell.

2212. RRCConnectionReconfigurationComplete(HANDOVER CONFIRM)

eNB Initiated Change of PPF Due to Changes of Characteristics

As the characteristics are known within the same eNB, eNB can by itselfdecide if change of PPF is needed or not. This procedure has bigsimilarity to intra-eNB handover case, where the eNB can setup a dataforwarding between PPF and then issue a path switch procedure forswitching path between CN and RAN.

In case CN endpoint also needs to be changed, the procedure according toFIG. 20 will be followed.

An example on eNB initiated change of PPF is shown in FIG. 23 below. Thenew sequences compare to the legacy are marked with dotted lines andunderlined text in the Figure. See the following example actions andmessages in FIG. 23 regarding eNB initiated change of PPF due to changesof characteristics. The new sequences compare to the legacy are markedwith dotted lines and underlined text.

2312. eNB decides to change PPF instance.

2314. eNB forward DL data from source PPF instance to target PPFinstance.

2315. eNB redirect UL data from source PPF instance to target PPFinstance

2317. Path Switch Request.

2318. MME decides no change on SGW endpoint and redirect DL data fromSGW to Target PPF.

2319. Path Switch Request Ack.

2320. eNB remove unused resource and DL forwarding path.

MME initiated change of PPF due to changes of characteristics Thisprocedure is possible as the characteristics of the neighboring eNB isalready known (already distributed during setup or accessible viaexternal DB). A new signaling procedure need to be created forinitialize PPF change on a certain UE, with new PPF-id as parameter. Theremaining procedure is the same as eNB initiated change of PPF case.

In case CN endpoint also needs to be changed, the procedure according toFIG. 13 will be followed.

See the following example actions and messages in FIG. 24 regarding MMEinitiated change of PPF due to changes of characteristics. The newsequences compare to the legacy are marked with dotted lines andunderlined text.

2411 z. MME decides to change PPF instance for UE.

2414. eNB forwards DL data from source PPF instance to target PPFinstance.

2415. eNB redirects UL data from source PPF instance to target PPFinstance.

2415 a. eNB endpoint Switch Request Ack( . . . ).

2417. Path Switch Request.

2418. MME decides no change on SGW endpoint and redirect DL data fromSGW to Target PPF instance.

2419. Path Switch Request Ack.

2420. eNB removes unused resource and DL forwarding path.

Characteristics Distribution Method to the Related RAN and CN Nodes, andMechanism for Controlling Transport Path Changes Such as Endpoint PairChanges During Cell Changes and/or Other Occasions—CharacteristicsDistribution During Demanding Occasion

Characteristics Distribution Principle

In this approach, Characteristics distribution during demandingoccasion, only necessary characteristics needed for the node will bestored locally in the radio network node 111 and CN node 130 such as theLTE eNB and MME. The information will be distributed between the nodesfirst when there is a need, e.g. during handover occasion, triggeringendpoint pair changes due to changes in characteristics.

The basic principles may be as follows:

1. The Source eNB, such as e.g. the radio network node 111 informs thetarget eNB, such as e.g. the radio network node 112 about used PPFinstances and possible PPF instances when a handover event is to betriggered, the source RAN includes information, such as e.g. PPFinstance identities, data center identities, and path characteristics.

2. The target eNB such as e.g. the network node 111, 112 evaluates ifthe used PPF instance can be re-used, or if a new PPF instances shouldbe selected.

-   -   a. If a new PPF instance should be selected, then a new S-GW may        need to be selected, the target eNB indicates this to the CN        node 130 such as the MME, the target eNB also includes        information about suitable PPF instances. I.e. information about        potential PFF instances, such as PPF instance identities, data        center identities, path characteristics.    -   b. The CN node 130 then selects a CN endpoint such as an S-GW        based on information received from the target eNB, and informs        the target eNB about a preferred PPF instance.

A possible variant for step 2 is that the CN node 130 such as the MMEinforms the target eNB that the CN endpoint such as the S-GW needs to bechanged, the CN node 130 may also include a list of preferred CNendpoint such as S-GWs and information about the S-GW, such as datacenter identities. Then the target eNB has the possibility to influencethe CN endpoint such as S-GW selection by providing information aboutpotential PPF instances, i.e. information about available PFF instances,such as PPF identities, data centre identities, path characteristics sothat the best CN endpoint Such as S-GW and PPF instance pair i.e.S-GW/PPF pair can be selected. This CN endpoint—PPF instance pair is thefirst part of the transport path as mentioned above.

The selection of S-GW/PPF endpoint pair may be per E-RAB.

In case of more than one radio path, e.g. dual connectivity orequivalent 5G concepts for multipath handling, the characteristics ofall relevant paths should be considered when proposing suitable PPFinstances.

The distribution of characteristics may be done through the followinginterfaces and procedures.

-   -   X2-AP: Handover Request    -   X2-AP: Handover Request Acknowledge    -   S1-AP: Path Switch Request    -   S1-AP: Path Switch Request Acknowledge    -   S1-AP: Handover Required    -   S1-AP: Handover Request

In some cases, new signals are also required for distribution during ondemand occasion. These new and modified sequences, e.g. addition ofinformation compared to the legacy are marked in bold text in FIGS.25-27 and is described in examples in the next chapter.

Change of Transport Path Such as Endpoint Pairs Occasions (IncludingCharacteristics Distribution), Example 1: Inter-eNB S1 Handover, withChanging of RAN/CN Endpoint Pairs, Characteristics Distributed on DemandOccasion

Handover signalling is preferably enhanced with information aboutselected data center and/or characteristics in order to facilitate theselection of suitable end point pairs.

Three different example implementations provided.

1. The Core NW such as the CN node 130 do not change CN endpoint such asS-GW, Target RAN such as the target radio network node checks if usedPPF can be kept.

2. Core NW such as the CN node 130 wants to change CN endpoint such asS-GW, early check with target radio network node if suitable PPFinstance is available.

3. Core NW such as the CN node 130 wants to change CN endpoint such asS-GW, late check with target radio network node and if no suitable PPFinstance, target radio network node initiates re-negotiation.

Common for the different variants is that the transparent container fromsource radio network node 111, such as the source eNB, includes newinformation about the used PPF instance, such as the PPF location, e.g.the AreaID that indicates used data center, and characteristics for theRAN transport path also referred as the second part of the transportpath.

Core NW do not Change S-GW, Target RAN Checks if Used PPF can be Kept

See the following example actions and messages in FIG. 25 regarding coreNW do not change S-GW, Target RAN checks if used PPF can be kept

1. The source eNB includes new information in the transparent container,i.e. information about the current used PPF instance, such as the PPFlocation, e.g. the AreaID that indicates used data center, andcharacteristics for the RAN path such as the second part of thetransport path.

2. The MME forwards this to the target eNB such as the second radionetwork node 112

3. The target eNB such as the second radio network node 112 checks ifthe used PPF instance is among the PPF instances the target eNB can use,and if the characteristics of the RAN path is good enough.

4. In this example the PPF instance can be reused, so the target eNBresponds with Handover request acknowledge.

5. The HO sequence continues.

If the PPF instance cannot be reused, i.e. check in step 3 failed, andthe target eNB is needed to select another PPF instance, the target eNBmay initiate a reselection of the CN endpoint such as S-GW as describedabove.

Core NW Such as the CN Node 130 Wants to Change CN Endpoint Such asS-GW, Early Check with Target eNB if Suitable PPF Instance is Available

See the following example actions and messages in FIG. 26 regarding CoreNW wants to change S-GW, early check with target eNB if suitable PPFinstance is available

1. Source eNB decides a HO is required and sends HandOver Requiredmessage to MME.

2. MME decides to change S-GW,

3. MME initiates a check with target eNB and sends information abouttarget (new) S-GW (e.g. AreaID for S-GW) to target eNB such as the radionetwork node 112 and forwards the received transparent container withinformation about used PPF instance in new message.

4. The target eNB checks if the used PPF instance can be reused withmaintained characteristics, e.g. if the S-GW and PPF instance arelocated in the same data center (indicated by same AreaID) and if theRAN path characteristics are sufficient. If PPF instance can be reusedand characteristics sufficient, the target eNB responds to MME thatselected S-GW is ok.

5. If the used PPF instance cannot be reused, the target RAN indicatesthis to MME and includes a list of available PPF instances, the relatedRAN characteristics and information about the PPF instances such as theAreaID. (the list could include one PPF). The MME can then select asuitable -S-GW. E.g. one S-GW located in the same data center (sameAreaId).

6. The MME indicates the selected S-GW in the Handover request messageto the target eNB.

7. The target eNB acknowledge the handover.

8. The HO sequence continues as normal.

Core NW Wants to Change S-GW, Late Check with Target RAN and if NoSuitable PPF, Target RAN Initiates Re-Negotiation

See the following example actions and messages in FIG. 27 regarding

1. Source eNB decides a HO is required and sends HandOver Requiredmessage to the CN node 130 such as the MME.

2. The MME decides to change CN endpoint such as S-GW,

3. The MME sends handover request to the target eNB such as the radionetwork node 111 and includes information about target (new) S-GW andthe received transparent container with information about used PPFinstance.

4. The target eNB checks if the used PPF instance can be reused withmaintained characteristics.

5. If the used PPF instance can be reused, can the target eNB respondsto MME that selected S-GW is ok with the handover request acknowledgemessage.

6. The handover sequence continues a normal, i.e. the below steps arenot executed.

7. If used PPF instance cannot be reused, the target RAN indicates thisto MME and includes a list of available PPF instances, the relatedcharacteristics and information about the PPF instances such as theAreaID, the list may include one PPF instance.

That no suitable PPF instance is available could be informed indifferent ways, e.g:

7a) New information in the handover failure message, that indicates thata S-GW reselection is needed and information about suitable PPFinstances.

7b) With a new message to indicate S-GW reselection and informationabout suitable PPF instances. These messages may also includeinformation about action to take if reselection of suitable S-GW fails,i.e. continue set-up with non optimal S-GW or drop session to prevent adeadlock.

8. The MME may then select a suitable -S-GW, e.g. with same AreaId asthe PPF instance and good RAN characteristics. The MME indicates theselected S-GW in the Handover request message to the target eNB.Possibly also indicate that set-up should continue even if not optimalPPF instance/S-GW pair.

The HO sequence continues as normal.

Change of Endpoint Pairs Occasions (Including CharacteristicsDistribution), Example 2: Inter-eNB X2 Handover, without Changing theRAN/CN Endpoint Pairs

The scenario describes the procedure of handing over a UE from oneeNodeB to another via X2 and changing the PPF. These examples alsoinvolves dual connectivity.

There are several possible scenarios, for example. FIG. 28 depicts threescenarios.

In scenario 1 the UE (A) has a single active air interface path in oneeNB and moves into another eNB (B). In this case the Transport Network(TN) path between antenna endpoint and PPF instance shall be switched toantenna endpoint in the new eNB from the serving PPF instance, or a newcandidate PPF instance shall be selected for the single path.

In scenario 2 the UE (A) has two active air interfaces paths via twoeNBs and moves into an area (B) where a new air interface path shall beadded, from the serving PPF instance to the new eNB, and an old oneremoved, or alternatively a new PPF instance shall be selected,connecting both paths. In LTE, this would be managed as a dualconnectivity case but it is assumed that 5G will support more multipathoptions. It shall also be noted that with the PPF instance beingseparated from the lower layers and potentially located at a higheraggregation level in the network Master eNB/Secondary eNB (MeNB/SeNB)roles of LTE may change and several changes may be introduced in variousinterfaces. The selection of a PPF shall preferably consider the pathsfrom all involved eNBs.

Scenario 3 is similar but in this case a path is added but none isremoved i.e. the target is three air interface paths and TN paths.

It shall also be noted that the PPF instance selection and pathstructure may be different for each E-RAB.

There are at least three options for the procedure:

1 Reselection of PPF instance during the handover completion phase onrequest from CN.

2 Coordinated reselection of PPF instance and S-GW between RAN and CNduring the handover preparation phase.

3 Speculative PPF instance reselection by RAN such as the radio networknode 111, during handover preparation with possible reselection duringhandover completion phase.

A TP is a Transmission Point or cell or similar in the descriptionbelow.

A Path refers to a connection between a PPF instance and the lowerlayers in an eNodeB/Secondary (S)eNB.

Option 1:

In this option the RAN such as the RAN 102 assumes that the serving PPFinstance of each E-RAB shall be kept until told otherwise by the CN 104,in which case a reselection will be done late, during the handovercompletion phase. Signaling related to multipath (e.g. dualconnectivity) is illustrative only.

The handover preparation phase signaling must be modified to allow allinvolved eNodeBs determine if the serving PPF instances may be used andto estimate the path cost of candidate PPF instances.

During the Handover Preparation Phase:

1 In the X2-AP: HANDOVER REQUEST message and for each E-RAB the sourceeNB shall include information that identifies the serving PPF instance,the path cost from each existing TP to the serving PPF instance and theidentity of the eNodeB controlling the TP. The serving PPF is identifiedwith the following IEs; 1) a ServingEntityEndpoint identifies the actualTNL (Transport Network Layer) address and GTP Tunnel Endpoint IDentifier(TEID) of the serving PPF, 2) an optional identifier ServingEntityAreaIDidentifies e.g. in which data center the PPF is located and 3) anoptional vendor specific transparent information element,ServingEntityInfo, identifies the PPF instance, and may carry otherparameters, in a vendor specific manner. The path costs are expressed interms of latency and obtainable bandwidth and potentially otherproperties. The identity of the controlling eNodeB of each TP isidentified using suitable IEs in the multipath case.

2 The target eNB such as the radio network node 111 allocates internalresources for every accepted E-RAB and performs a RAN internal path costcalculation between the TP selected for handover, the allocated andpotentially dispersed internal resources, and each candidate PPF(including the serving PPF).

The cost calculation may be based on actual or configuredcharacteristics between these internal resources and the PPF instance orsynthetic cost figures assigned to the PPF instances. Characteristicsinclude at least latency but can also include obtainable bandwidth andother parameters. The list may be stored for use during the handovercompletion phase.

For each accepted E-RAB the target eNB also validates that it hasconnectivity towards the serving PPF instance from the internalresources. This can be done in a variety of ways e.g. by querying an SDNdatabase using some unique identifier of the entities, performing aconnection test towards the PPF instance or accessing already availableinformation about established connections between the internal resourcesand any available PPF instances.

3 Conditionally, if there is more than one eNodeB providing paths to theUE, each applicable secondary eNodeB is contacted.

4 Each SeNB performs a similar path cost estimation from its internalresources to each candidate PPF instance.

5 A message containing the path cost estimations of each E-RAB andcandidate PPF is returned.

6 If any serving PPF instance is unreachable from the target eNodeB therequest is rejected with X2-AP: HANDOVER PREPARATION FAILURE and an S1handover procedure may be attempted by the source eNodeB. The resourcesin the target eNodeB are released.

7 The target eNodeB responds with X2-AP: HANDOVER REQUEST ACKNOWLEDGE astoday.

8 For each accepted E-RAB the source eNodeB modifies each serving PPF toforward down link packets to the target eNodeB and stop sending packetsto the Source eNodeB or alternatively the packets are duplicated forsome time.

The UE may then be ordered to tune to the target eNodeB.

The handover completion signaling is preferably enhanced withinformation about the ranked PPF instances and characteristics tofacilitate a possible reselection of suitable transport path such asend-point pairs. With reference to the X2 handover sequence from 3GPP23.401 below, the messages that need additional information is pointedout.

1 The target eNodeB such as the radio network node 111 sends messageS1-AP: PATH SWITCH REQUEST. It contains the existing IE E-RABs To BeSwitched in Uplink Item. The existing sub-IE TNL address identifies theserving PPF TNL end-point of each E-RAB. In addition, the serving PPF isidentified by two new optional sub-IEs; ServingAreaID identifying thedata center or area in which the PPF is located and ServingEntityInfo, atransparent vendor specific IE. It also contains a characteristics IEfor the serving PPF. A new sub-IE DIEntityList contains the list ofpossible PPFs identified by the AreaID and/or EntityInfo and containingthe path characteristics. If multi-path is used this would be anaggregated path cost.

2 SEE NEXT SEQUENCE

3 Once the target PPF instances s and GWs are allocated the downlinktransmission is rerouted from the target GWs to the target PPFinstances. The target PPF instance distributed the packets to allinvolved eNodeBs.

4 The MME indicates that the switch is complete.

5 The target eNodeB releases the resources in the source eNodeB.

6 The target eNodeB releases the resources in the source PPF instance.

Continuation:

1 If the S-GW shall be changed for one or more E-RABs, based on he theprovided DIEntityList and other parameters, the MME will allocate newtarget S-GWs using for instance the existing S11-AP: CREATE SESSIONREQUEST message, but modification of the PDN GW will not be done yet.

2 The MME will send a new message S1-AP: PATH MODIFICATION REQUEST tothe target eNodeB including all E-RABs to be modified and the new targetGW TNL address and GTP TEID for each E-RAB. It will also include an IEPreferredDIEntity identifying the preferred PPF the from the listprovided by the target eNodeB in the previous sequence.

3 For each modified E-RAB the target eNodeB such as the radio networknode 112 will allocate a new resource in the preferred PPF instanceusing some suitable message. The message includes the DL TNL address andGTP TEID for each involved eNodeB/SeNB and the target GW information andother parameters e.g. for security. If resources cannot be allocated inthe preferred PPF instance the eNodeB may attempt another PPF instanceaccording to some cost algorithm with the target GW as CN anchor. Thissequence is not covered here. If no PPF instance can be found theexisting PPF instance will be kept, if the CN has not ordered a releasein this case.

4 The PPF will return its own UL TNL address and GTP TEID for eachinvolved path as well as a DL forwarding TNL address and GTP TEID. Thetarget eNodeB will modify its resources to expect traffic from thetarget PPF instance.

5 A message is sent to each SeNB to order it to modify its resources toexpect traffic from the target PPF and modify the source PPF instance toforward traffic to the target PPF instance. Note that this is optional.The SeNB may easily accept traffic from any source and use that sourcefor UL traffic. This requires that the link is secure to avoideavesdropping and similar.

6 The source PPF instance will be order to forward packets to the targetPPF instance using the DL FW address and TEID.

7 The target eNodeB will respond to the modification specifying the TNLaddress and GTP TEID of the target PPF for each modified E-RAB. OnlyE-RABs for which a new PPF was allocated are included.

8 For each E-RAB the MME will then modify the session including the TNLaddress and GTP TEID of the target PPF. At this point the Target GW willmodify the PDN GW.

The continuation is the same as today.

Option 2:

During the handover preparation phase the first part of the sequence isthe same as for OPTION 1:

The preparation phase continues per the sequence below:

1 The target eNodeB such as the radio network node 112 sends forinstance a modified S1-AP: E-RAB Modification Indication to the MME. Foreach accepted E-RAB the serving PPF is identified by ServingAreaID andServingEntityId and the characteristics of the path from the new TP, viainternal target eNodeB resources, to the serving PPF is included. A listof possible PPF instances is included in IE DIEntityInfo together withcharacteristics. Each one is similarly identified by AreaID and EntityIdand the path characteristics are included. If multi-path is used thiswould be an aggregated path cost.

2 If the S-GW shall be changed for one or more E-RABs the MME willallocate new target S-GWs using existing S11-AP: CREATE SESSION REQUESTbut modification of the PDN GW will not be done here.

3 The MME responds with a modified S1-AP: E-RAB ModificationConfirmation including, for every modified E-RAB, the TNL address andGTP TEID of new S-GW, and a preferred PPF instance.

4 For each modified E-RAB the target eNodeB allocates the preferred PPFinstance. If this is not possible the eNodeB may reattempt with someother PPF instance. This is not covered here. As in option 1 the targeteNodeB modifies its internal resources to expect traffic from the newPPF instance. The same reconfiguration is also done towards any SeNB.

5 The target eNodeB responds with X2-AP: HANDOVER REQUEST ACKNOWLEDGE,including the target PPF TNL address and GTP TEID for each acceptedE-RAB.

6 The source eNodeB modifies the serving PPF to forward traffic to thetarget PPF instance and the target PPF instance will forward to thetarget eNodeB resource.

The handover completion signaling is in this case straight forward.

1 A Path Switch Request is sent to the MME containing the address andTEID of the PPF for each E-RAB. Information required for reselection isstill included in case the CN state has changed.

2 For each modified E-RAB a S11-AP: Modify Session Request is sent tothe new target GW, selected during preparation. The GW modifies thebearer in the PDN GW to route new traffic to the target GW. Forunmodified E-RABs the MME will take no action.

The continuation is the same as in option 1. As the selection is alreadyagreed it is not envisioned that the MME will reselect GW at this point.If it does the handling would be the same as in option 1.

Option 3:

In this option the RAN such as RAN 102 performs a speculativereselection early based on known CN end-points or alternatively onlyconsidering what is best from a RAN point of view i.e. the path costbetween eNodeB/SeNBs and available PPFs. The CN 104 may trigger a secondreselection.

During the handover preparation phase the first part of the sequence isthe same as for OPTION 1.

Following the cost estimation and validation:

1 For each E-RAB to be setup the target eNodeB such as the radio networknode 111 determines the best PPF instance from a RAN point of view. Ifthere is knowledge of CN end-points i.e. available GWs, RAN may includeassumed characteristics of these end-points in the algorithm. Notehowever that the CN may still decide to make a different allocationbased on parameters not available to the RAN, such as load for instance.The RAN may also simply decide to assume that the CN will not changeGWs. The target eNodeB will then allocate new PPF instances and informany SeNBs.

The continuation is the same as for option 2, step 5 and onwards.

The completion phase is identical to option 2.

According to embodiments herein the characteristics requirement of eachdata stream between radio network node 111 and the CN 104 are fulfilled,and also embodiments herein maximize the number of data streams betweenradio network node 111 and the CN 104 fulfilling the characteristicsrequirement of the streams, in a network where a radio network node 111comprises multiple endpoints such as antenna endpoints.

To perform the method actions for controlling whether or not to change atransport path for a user plane session in a radio communicationsnetwork 100, the network node 111, 112, 130 may comprise the followingarrangement depicted in FIG. 29. The path is adapted to prolong along afirst part between an antenna endpoint of a network node 111 and a PPFinstance PPF1, PPF2, PPF3 serving the network node 111 and a second partbetween the PPF instance PPF1, PPF2, PPF3 and the CN endpoint 1411,1412, 1421.

The network node 111, 112, 130 comprises an input and output interface2900 configured to communicate, with the wireless device 120, the PPFinstances PPF1, PPF2, PPF3, one or more network nodes such as radionetwork nodes and core network nodes, e.g. the first and/or secondgateway node 141, 142, RAN nodes such as the Network node 111, 112, 130,and/or O&M nodes. The input and output interface 2900 may comprise areceiver (not shown) and a transmitter (not shown). The radio networknode 111, 112 may also comprise one or more PPF instances and one ormore PPF instances have interfaces (RAN endpoint) which is pooledbetween eNBs such as the radio network node 111 and the second networknode 112.

The network node 111, 112, 130 is configured to, e.g. by means of anidentifying module 2910 configured to identify available CN endpoints1411, 1412, 1421 in the CN 104, available PPF instances PPF1, PPF2, PPF3in the RAN 102, and of available antenna endpoints 1111, 1112, 1121,1122 in the RAN 102. The available CN endpoints 1411, 1412, 1421,available PPF instances PPF1, PPF2, PPF3 and available antenna endpoints1111, 1112, 1121, 1122 are adapted to be available for the user planesession and comprise a number of possible transport paths for the userplane session.

The network node 111, 112, 130 is further configured to, e.g. by meansof an obtaining module 2920 configured to obtain characteristics ofavailable first parts of the possible transport paths, andcharacteristics of available second parts of the possible transportpaths.

The network node 111, 112, 130 is further configured to, e.g. by meansof an controlling module 2930 configured to, when detecting a changeevent related to the user plane session, control whether or not tochange the transport path to any of the a number of possible transportpaths for the user plane session based on the obtained characteristicsof available first parts of the transport path, and characteristics ofavailable second parts of the transport path.

The characteristics of the available first parts of the transport path,and the characteristics of the available second parts of the transportpath may be adapted to be obtained in advance of any change eventrelated to the user plane session.

The characteristics of the available first parts of the transport path,and characteristics of the available second parts of the transport pathmay as an alternative be adapted to be obtained during the detectedchange event related to the user plane session.

The characteristics of any one or more out of: the available first partsof the transport path and the available second parts of the transport,may be adapted to relate to: any one or more out of:

latency of said first part and/or second part,

obtainable bandwidth of said first part and/or second part,

number of active sessions in said first part and/or second part,

bandwidth usage of said first part and/or second part,

monetary transmission cost of said first part and/or second part, and

any variables which provides preference of said first part and/or secondpart.

In some embodiments, the characteristics of the available first parts ofthe transport path, and characteristics of the available second parts ofthe transport may be adapted to relate to latency. In these embodiments,the network node 111, 112, 130 may further be configured to controlwhether or not to change the transport path to any of the a number ofpossible transport paths for the user plane session based on selectingthe transport path with lowest delay.

In some embodiments, the characteristics of the available first parts ofthe transport path, and characteristics of the available second parts ofthe transport are adapted to relate to bandwidth. In these embodiments,the network node 111, 112, 130 may further be configured to controlwhether or not to change the transport path to any of the a number ofpossible transport paths for the user plane session, based on selectingthe transport path with broadest bandwidth.

In some embodiments, the characteristics of the available first parts ofthe transport path, and characteristics of the available second parts ofthe transport are adapted to relate to latency and bandwidth. In theseembodiments, the network node 111, 112, 130 may further is configured tocontrol whether or not to change the transport path to any of the anumber of possible transport paths for the user plane session, based onselecting a transport path with lowest delay and broadest bandwidth.

The detected change event adapted to relate to the user plane sessionmay e.g. comprise any one or more out of:

A handover decision,

adding a carrier related to carrier aggregation and setting up orchanging a dual connectivity,

a change of PPF instance PPF1, PPF2, PPF3 initiated by the network node111 due to changes of characteristics, and

a change of PPF instance PPF1, PPF2, PPF3 initiated by a core networknode 130 due to changes of characteristics.

In some embodiments, any one or more out of the characteristics of theavailable first parts of the possible transport paths, and thecharacteristics of the available second parts of the possible transportpaths, may be adapted to be obtained in any one out of:

A static configuration, wherein the characteristics are stored in a database 150 when a new available CN endpoint 1411, 1412, 1421, availablePPF instance PPF1, PPF2, PPF3 and/or available antenna endpoint isintroduced, and

an autonomous configuration, wherein the characteristics are obtained by

a) obtaining measurements of the respective available first part andsecond part of the number of possible transport paths,

b) matching identities related to the characteristics of the respectiveavailable CN endpoints 1411, 1412, 1421, available PPF instances PPF1171, PPF2 172, PPF3 173, and/or available antenna endpoints.

The embodiments herein for controlling whether or not to change atransport path for a user plane session in a radio communicationsnetwork 100, the network node 111, 112, 130 may be implemented throughone or more processors, such as a processor 2940 of a processingcircuitry in the network node 111, 112, 130 depicted in FIG. 29,together with computer program code for performing the functions andactions of the embodiments herein. The program code mentioned above mayalso be provided as a computer program product, for instance in the formof a data carrier carrying computer program code for performing theembodiments herein when being loaded into network node 111, 112, 130.One such carrier may be in the form of a CD ROM disc. It is howeverfeasible with other data carriers such as a memory stick. The computerprogram code may furthermore be provided as pure program code on aserver and downloaded to the network node 111, 112, 130.

The network node 111, 112, 130 may further comprise a memory 2950comprising one or more memory units. The memory 2950 comprisesinstructions executable by the processor 2940.

The memory 2950 is arranged to be used to store e.g. identifiers of anyone or more out of: the available CN endpoints 1411, 1412, 1421,available antenna endpoints 1111, 1112, 1121, 1122, first and secondparts of transport paths, CN/RAN endpoint pairs, configurationinformation, feedback, data, and applications to perform the methodsherein when being executed in the network node 111, 112, 130.

In some embodiments, a computer program 2960 comprises instructions,which when executed by the at least one processor 2940, cause the atleast one processor 2940 to perform actions according to any of theActions 1801-1806.

In some embodiments, a carrier 2970 comprises the computer program 2960,wherein the carrier is one of an electronic signal, an optical signal,an electromagnetic signal, a magnetic signal, an electric signal, aradio signal, a microwave signal, or a computer-readable storage medium.

Those skilled in the art will also appreciate that the modules in thenetwork node 111, 112, 130, described above may refer to a combinationof analog and digital circuits, and/or one or more processors configuredwith software and/or firmware, e.g. stored in the memory 2950, that whenexecuted by the one or more processors such as the processor 2940 asdescribed above. One or more of these processors, as well as the otherdigital hardware, may be included in a single Application-SpecificIntegrated Circuitry (ASIC), or several processors and various digitalhardware may be distributed among several separate components, whetherindividually packaged or assembled into a system-on-a-chip (SoC).

The invention claimed is:
 1. A method performed by a network node forcontrolling whether or not to change a transport path for a user planesession in a radio communications network, which path prolongs along: afirst part between an antenna endpoint of a network node and a PacketProcessing Function (PPF) instance serving the network node and a secondpart between the PPF instance and a Core Network (CN) endpoint, themethod comprising: identifying available CN endpoints in a CN, availablePPF instances in a Radio Access Network (RAN) and of available antennaendpoints in the RAN, which available CN endpoints, available PPFinstances and available antenna endpoints are available for the userplane session and comprises a number of possible transport paths for theuser plane session; obtaining characteristics of available first partsof the possible transport paths, and characteristics of available secondparts of the possible transport paths; and when detecting a change eventrelated to the user plane session, controlling whether or not to changethe transport path to any of the a number of possible transport pathsfor the user plane session based on the obtained characteristics ofavailable first parts of the transport path, and characteristics ofavailable second parts of the transport path.
 2. The method according toclaim 1, wherein the characteristics of the available first parts of thetransport path, and the characteristics of the available second parts ofthe transport path are obtained in advance of any change event relatedto the user plane session.
 3. The method according to claim 1, whereinthe characteristics of the available first parts of the transport path,and the characteristics of the available second parts of the transportpath are obtained during the detected change event related to the userplane session.
 4. The method according to claim 1, wherein thecharacteristics of any one or more out of: the available first parts ofthe transport path and the available second parts of the transportrelate to any one or more out of: latency of said first part, or secondpart, or both said first and second parts; obtainable bandwidth of saidfirst part, or second part, or both said first and second parts; numberof active sessions in said first part, or second part, or both saidfirst and second parts; bandwidth usage of said first part, or secondpart, or both said first and second parts; monetary transmission cost ofsaid first part, or second part, or both said first and second parts;and any variables which provides preference of said first part, orsecond part, or both said first and second parts.
 5. The methodaccording to claim 1, wherein the characteristics of the available firstparts of the transport path, and characteristics of the available secondparts of the transport relate to latency, and wherein controllingwhether or not to change the transport path to any of the a number ofpossible transport paths for the user plane session is based onselecting the transport path with lowest delay.
 6. The method accordingto claim 1, wherein the characteristics of the available first parts ofthe transport path, and characteristics of the available second parts ofthe transport relate to bandwidth, and wherein controlling whether ornot to change the transport path to any of the a number of possibletransport paths for the user plane session is based on selecting thetransport path with broadest bandwidth.
 7. The method according to claim1, wherein the characteristics of the available first parts of thetransport path, and characteristics of the available second parts of thetransport relate to latency and bandwidth, and wherein controllingwhether or not to change the transport path to any of the a number ofpossible transport paths for the user plane session is based onselecting a transport path with lowest delay and broadest bandwidth. 8.The method according to claim 1, wherein the detected change eventrelated to the user plane session comprises any one or more out of: ahandover decision; adding a carrier related to carrier aggregation andsetting up or changing a dual connectivity; a change of PPF instanceinitiated by the network node due to changes of characteristics; and achange of PPF instance initiated by a core network node due to changesof characteristics.
 9. The method according to claim 1, wherein thecharacteristics of available first parts of the possible transportpaths, and characteristics of the available second parts of the possibletransport paths, are obtained in any one out of: a static configuration,wherein the characteristics are stored in a data base when one or moreof a new available CN endpoint, available PPF instance, and availableantenna endpoint is introduced; and an autonomous configuration, whereinthe characteristics are obtained by: (a) obtaining measurements of therespective available first part and second part of the number ofpossible transport paths; and (b) matching identities related to thecharacteristics of one or more of the respective available CN endpoints,available PPF instances, and available antenna endpoints.
 10. Anon-transitory computer readable storage medium, having stored thereon acomputer program comprising instructions which, when executed by aprocessor, are capable of causing the processor to perform operationsfor a network node to control whether or not to change a transport pathfor a user plane session in a radio communications network, which pathprolongs along: a first part between an antenna endpoint of a networknode and a Packet Processing Function (PPF) instance serving the networknode and a second part between the PPF instance and a Core Network (CN)endpoint, the operations comprising: identifying available CN endpointsin a CN, available PPF instances in a Radio Access Network (RAN) and ofavailable antenna endpoints in the RAN, which available CN endpoints,available PPF instances and available antenna endpoints are availablefor the user plane session and comprises a number of possible transportpaths for the user plane session; obtaining characteristics of availablefirst parts of the possible transport paths, and characteristics ofavailable second parts of the possible transport paths; and whendetecting a change event related to the user plane session, controllingwhether or not to change the transport path to any of the a number ofpossible transport paths for the user plane session based on theobtained characteristics of available first parts of the transport path,and characteristics of available second parts of the transport path. 11.A network node for controlling whether or not to change a transport pathfor a user plane session in a radio communications network, which pathis adapted to prolong along: a first part between an antenna endpoint ofa network node and a Packet Processing Function (PPF) instance servingthe network node, and a second part between the PPF instance and a CoreNetwork (CN) endpoint, the network node being configured to: identifyavailable CN endpoints in a CN, available PPF instances in a RadioAccess Network (RAN), and of available antenna endpoints in the RAN,which available CN endpoints, available PPF instances and availableantenna endpoints are adapted to be available for the user plane sessionand comprise a number of possible transport paths for the user planesession; obtain characteristics of available first parts of the possibletransport paths, and characteristics of available second parts of thepossible transport paths; and when detecting a change event related tothe user plane session, control whether or not to change the transportpath to any of the a number of possible transport paths for the userplane session based on the obtained characteristics of available firstparts of the transport path, and characteristics of available secondparts of the transport path.
 12. The network node according to claim 11,wherein the characteristics of the available first parts of thetransport path, and the characteristics of the available second parts ofthe transport path are adapted to be obtained in advance of any changeevent related to the user plane session.
 13. The network node accordingto claim 11, wherein the characteristics of the available first parts ofthe transport path, and characteristics of the available second parts ofthe transport path are adapted to be obtained during the detected changeevent related to the user plane session.
 14. The network node accordingto claim 11, wherein the characteristics of any one or more out of: theavailable first parts of the transport path and the available secondparts of the transport, are adapted to relate to: any one or more outof: latency of said first part, or second part, or both said first andsecond parts; obtainable bandwidth of said first part, or second part,or both said first and second parts; number of active sessions in saidfirst part, or second part, or both said first and second parts;bandwidth usage of said first part, or second part, or both said firstand second parts; monetary transmission cost of said first part, orsecond part, or both said first and second parts; and any variableswhich provides preference of said first part, or second part, or bothsaid first and second parts.
 15. The network node according to claim 11,wherein the characteristics of the available first parts of thetransport path, and characteristics of the available second parts of thetransport are adapted to relate to latency and wherein the network nodefurther is configured to control whether or not to change the transportpath to any of the a number of possible transport paths for the userplane session based on selecting the transport path with lowest delay.16. The network node according to claim 11, wherein the characteristicsof the available first parts of the transport path, and characteristicsof the available second parts of the transport are adapted to relate tobandwidth, and wherein the network node further is configured to controlwhether or not to change the transport path to any of the a number ofpossible transport paths for the user plane session, based on selectingthe transport path with broadest bandwidth.
 17. The network nodeaccording to claim 11, wherein the characteristics of the availablefirst parts of the transport path, and characteristics of the availablesecond parts of the transport are adapted to relate to latency andbandwidth, and wherein the network node further is configured to controlwhether or not to change the transport path to any of the a number ofpossible transport paths for the user plane session, based on selectinga transport path with lowest delay and broadest bandwidth.
 18. Thenetwork node according to claim 11, wherein the detected change eventadapted to relate to the user plane session comprises any one or moreout of: a handover decision; adding a carrier related to carrieraggregation and setting up or changing a dual connectivity; a change ofPPF instance initiated by the network node due to changes ofcharacteristics; and a change of PPF instance initiated by a corenetwork node due to changes of characteristics.
 19. The network nodeaccording to claim 11, wherein any one or more out of thecharacteristics of the available first parts of the possible transportpaths, and the characteristics of the available second parts of thepossible transport paths, are adapted to be obtained in any one out of:a static configuration, wherein the characteristics are stored in a database when one or more of a new available CN endpoint, available PPFinstance and available antenna endpoint is introduced; and an autonomousconfiguration, wherein the characteristics are obtained by: (a)obtaining measurements of the respective available first part and secondpart of the number of possible transport paths; and (b) matchingidentities related to the characteristics of one or more of therespective available CN endpoints, available PPF instances, andavailable antenna endpoints.